e424b5
Table of Contents

The information in this prospectus supplement and the accompanying prospectus is not complete and may be changed. This prospectus supplement and the accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in any jurisdiction where this offer or sale is not permitted.
 
 
Filed Pursuant to Rule 424(b)(5)
Registration File No. 333-133889
 
Subject to Completion
Preliminary Prospectus Supplement dated January 26, 2009
 
PROSPECTUS SUPPLEMENT
(To prospectus dated May 8, 2006)
 
8,000,000 Shares
 
(WHITING LOGO)
 
Whiting Petroleum Corporation
 
Common Stock
 
 
We are offering 8,000,000 shares of our common stock. Our common stock is traded on the New York Stock Exchange under the symbol “WLL.” On January 23, 2009, the last sale price of our common stock as reported on the New York Stock Exchange was $33.94 per share.
 
Investing in our common stock involves risks that are described in the “Risk Factors” section beginning on page S-16 of this prospectus supplement.
 
 
         
   
Per Share
 
Total
 
Public offering price
  $   $
         
Underwriting discount
  $   $
         
Proceeds, before expenses, to us
  $   $
 
The underwriters may also purchase up to an additional 1,200,000 shares from us at the public offering price, less the underwriting discount, within 30 days from the date of this prospectus supplement to cover overallotments.
 
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.
 
The shares will be ready for delivery on or about          , 2009.
 
 
Book-Running Manager
 
Merrill Lynch & Co.
 
 
         
J.P. Morgan
Barclays Capital
Jefferies & Company
  KeyBanc Capital Markets
RBC Capital Markets
  Raymond James
Wachovia Securities
Tristone Capital
 
 
 
The date of this prospectus supplement is          , 2009.


Table of Contents


Table of Contents


 

TABLE OF CONTENTS
 
Prospectus Supplement
 
         
    Page
 
    ii  
    ii  
    iii  
    S-1  
    S-16  
    S-28  
    S-29  
    S-30  
    S-31  
    S-34  
    S-35  
    S-35  
 
Prospectus
 
         
    Page  
 
About This Prospectus
    2  
Special Note Regarding Forward-Looking Statements
    3  
Whiting Petroleum Corporation
    3  
Selling Stockholders
    3  
Use of Proceeds
    4  
Ratio of Earnings to Fixed Charges
    4  
Description of Debt Securities
    4  
Description of Capital Stock
    18  
Description of Warrants
    21  
Description of Stock Purchase Contracts and Stock Purchase Units
    22  
Where You Can Find More Information
    22  
Plan of Distribution
    23  
Legal Matters
    25  
Experts
    25  


i


Table of Contents

 
ABOUT THIS PROSPECTUS SUPPLEMENT
 
This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering. The second part, the accompanying prospectus, gives more general information, some of which may not apply to this offering. You should read the entire prospectus supplement, as well as the accompanying prospectus and the documents incorporated by reference that are described under “Where You Can Find More Information” in this prospectus supplement and the accompanying prospectus. In the event that the description of this offering varies between this prospectus supplement and the accompanying prospectus, you should rely on the information contained in this prospectus supplement.
 
You should rely only on the information contained in this prospectus supplement and the accompanying prospectus. We have not, and the underwriters have not, authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information appearing in this prospectus supplement and the accompanying prospectus is accurate only as of the date on their respective front covers. Our business, financial condition, results of operations and prospects may have changed since those dates.
 
In this prospectus supplement, “we,” “us,” “our” or “ours” refer to Whiting Petroleum Corporation and its consolidated subsidiaries.
 
GLOSSARY OF CERTAIN OIL AND GAS TERMS
 
We have included below the definitions for certain oil and gas terms used in this prospectus supplement:
 
3-D seismic” Geophysical data that depict the subsurface strata in three dimensions. 3-D seismic typically provides a more detailed and accurate interpretation of the subsurface strata than 2-D, or two-dimensional, seismic.
 
Bbl” One stock tank barrel, or 42 U.S. gallons liquid volume, used in this prospectus supplement in reference to oil and other liquid hydrocarbons.
 
Bcf” One billion cubic feet of natural gas.
 
BOE” One stock tank barrel equivalent of oil, calculated by converting natural gas volumes to equivalent oil barrels at a ratio of six Mcf to one Bbl of oil.
 
BOE/d” One BOE per day.
 
CO2 flood” A tertiary recovery method in which CO2 is injected into a reservoir to enhance hydrocarbon recovery.
 
completion” The installation of permanent equipment for the production of oil or natural gas, or in the case of a dry hole, the reporting of abandonment to the appropriate agency.
 
GAAP” Generally accepted accounting principles in the United States of America.
 
MBOE” One thousand BOE.
 
MBOE/d” One MBOE per day.
 
Mcf” One thousand cubic feet of natural gas.
 
MMBbl” One million Bbl.
 
MMBOE” One million BOE.
 
MMBtu” One million British Thermal Units.
 
MMcf” One million cubic feet of natural gas.
 
MMcf/d” One MMcf per day.


ii


Table of Contents

net revenue interest” The interest owned in the revenues of a crude oil and natural gas property, after all royalties, overriding royalties and other burdens have been deducted from the working interest.
 
plugging and abandonment” Refers to the sealing off of fluids in the strata penetrated by a well so that the fluids from one stratum will not escape into another or to the surface. Regulations of many states require plugging of abandoned wells.
 
pre-tax PV10%” The present value of estimated future revenues to be generated from the production of proved reserves calculated in accordance with the guidelines of the Securities and Exchange Commission, or the SEC, net of estimated lease operating expense, production taxes and future development costs, using price and costs as of the date of estimation without future escalation, without giving effect to non-property related expenses such as general and administrative expenses, debt service and depreciation, depletion and amortization, or Federal income taxes and discounted using an annual discount rate of 10%.
 
reservoir” A porous and permeable underground formation containing a natural accumulation of producible oil and/or natural gas that is confined by impermeable rock or water barriers and is individual and separate from other reservoirs.
 
resource play” Refers to drilling programs targeted at regionally distributed oil or natural gas accumulations. Successful exploitation of these reservoirs is dependent upon new technologies such as horizontal drilling and multi-stage fracture stimulation to access large rock volumes in order to produce economic quantities of oil or natural gas.
 
working interest” The interest in a crude oil and natural gas property (normally a leasehold interest) that gives the owner the right to drill, produce and conduct operations on the property and a share of production, subject to all royalties, overriding royalties and other burdens and to all costs of exploration, development and operations and all risks in connection therewith.
 
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
 
This prospectus supplement, the accompanying prospectus and the documents incorporated by reference contain statements that we believe to be “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. All statements other than historical facts, including, without limitation, statements regarding our future financial position, business strategy, projected revenues, earnings, costs, capital expenditures and debt levels, and plans and objectives of management for future operations, are forward-looking statements. When used in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference, words such as we “expect,” “intend,” “plan,” “estimate,” “anticipate,” “believe” or “should” or the negative thereof or variations thereon or similar terminology are generally intended to identify forward-looking statements. Such forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements. These risks and uncertainties include, but are not limited to:
 
  •      declines in oil or natural gas prices;
 
  •      impacts of the global financial crisis;
 
  •      our level of success in exploitation, exploration, development and production activities;
 
  •      adverse weather conditions that may negatively impact development or production activities;
 
  •      the timing of our exploration and development expenditures, including our ability to obtain drilling rigs and CO2;
 
  •      inaccuracies of our reserve estimates or our assumptions underlying them;
 
  •      revisions to reserve estimates as a result of changes in commodity prices;


iii


Table of Contents

 
  •      risks related to our level of indebtedness and periodic redeterminations of Whiting Oil and Gas Corporation’s borrowing base under our credit agreement;
 
  •      our ability to generate sufficient cash flows from operations to meet the internally funded portion of our capital expenditures budget;
 
  •      our ability to obtain external capital to finance exploration and development operations and acquisitions;
 
  •      our ability to identify and complete acquisitions and to successfully integrate acquired businesses;
 
  •      unforeseen underperformance of or liabilities associated with acquired properties;
 
  •      our ability to successfully complete potential asset dispositions;
 
  •      failure of our properties to yield oil or gas in commercially viable quantities;
 
  •      uninsured or underinsured losses resulting from our oil and gas operations;
 
  •      our inability to access oil and gas markets due to market conditions or operational impediments;
 
  •      the impact and costs of compliance with laws and regulations governing our oil and gas operations;
 
  •      our ability to replace our oil and natural gas reserves;
 
  •      any loss of our senior management or technical personnel;
 
  •      competition in the oil and gas industry in the regions in which we operate;
 
  •      risks arising out of our hedging transactions; and
 
  •      other risks described under the caption “Risk Factors.”
 
We assume no obligation, and disclaim any duty, to update the forward-looking statements in this prospectus supplement, the accompanying prospectus or the documents we incorporate by reference. We urge you to carefully review and consider the disclosures made in this prospectus supplement, the accompanying prospectus and our reports filed with the SEC and incorporated by reference herein that attempt to advise interested parties of the risks and factors that may affect our business.


iv


Table of Contents

 
PROSPECTUS SUPPLEMENT SUMMARY
 
This summary highlights information contained elsewhere in this prospectus supplement and the accompanying prospectus. This summary may not contain all of the information that may be important to you. You should read the entire prospectus supplement, including “Risk Factors,” the accompanying prospectus and the documents we incorporate by reference into this prospectus supplement and the accompanying prospectus carefully before making a decision to invest in our common stock We have provided definitions for the oil and gas terms used in this prospectus supplement in the “Glossary of Certain Oil and Gas Terms” included in this prospectus supplement.
 
About Our Company
 
We are an independent oil and gas company engaged in oil and gas acquisition, development, exploitation, production and exploration activities primarily in the Permian Basin, Rocky Mountains, Mid-Continent, Gulf Coast and Michigan regions of the United States. Prior to 2006, we generally emphasized the acquisition of properties that increased our production levels and provided upside potential through further development. Since 2006, we have focused primarily on organic drilling activity and on the development of previously acquired properties, specifically on projects that we believe provide the opportunity for repeatable success and production growth. We believe the combination of acquisitions, subsequent development and organic drilling provides us a broad set of growth alternatives and allows us to direct our capital resources to what we believe to be the most advantageous investments.
 
As demonstrated by our recent capital expenditure programs, we are increasingly focused on a balance between exploration and development while continuing to selectively pursue acquisitions that complement our existing core properties. Our growth plan is centered on the following activities:
 
  •      pursuing the development of projects that we believe will generate attractive rates of return;
 
  •      maintaining a balanced portfolio of lower risk, long-lived oil and gas properties that provide stable cash flows;
 
  •      seeking property acquisitions that complement our core areas; and
 
  •      allocating an increasing percentage of our capital budget to leasing and exploring prospect areas.
 
We believe that our significant drilling inventory, combined with our operating experience and cost structure, provides us with meaningful organic growth opportunities. Additionally, we expect to continue to build on our successful acquisition track record and selectively pursue property acquisitions that complement our existing core properties. During 2008, we incurred $1,390.5 million in acquisition, development and exploration activities, including $947.0 million for the drilling of 306 gross (125.4 net) wells. Of these new wells, 115.3 (net) resulted in productive completions and 10.2 (net) were unsuccessful, yielding a 92% success rate.
 
On January 20, 2009, we announced a capital budget of $320.4 million for development and exploration expenditures in 2009 that we expect to fund from internally generated cash flows. We will use this 2009 base capital budget to continue development of our Northern and Central Rockies projects as well as our CO2 projects. After using the net proceeds from this offering to temporarily reduce amounts outstanding under our credit facility, we expect to use a portion of the proceeds from this offering to increase our 2009 base capital budget by approximately $123.6 million to develop incremental opportunities we have identified in the Northern and Central Rockies. However, we may allocate this portion of the proceeds as well as the balance of the proceeds from this offering to either further develop these incremental projects or to expand the projects in our 2009 base capital budget that indicate the highest return based on drilling results through the time of such allocation. Additional detailed information with respect to our 2009 base capital budget as well as prospects to be drilled with proceeds from this offering is presented below.


S-1


Table of Contents

As of December 31, 2008, our estimated proved reserves totaled 239.1 MMBOE, of which 67% were classified as proved developed. These estimated reserves had a pre-tax PV10% value of approximately $1,603.0 million, of which approximately 89% came from properties located in our Permian Basin, Rocky Mountains and Mid-Continent core areas. The following table summarizes our estimated proved reserves as of December 31, 2008 by core area, the corresponding pre-tax PV10% value and our December 2008 average daily production rate:
 
                                                 
    Proved Reserves        
                            Pre-Tax
    December 2008
 
                            PV10%
    Average Daily
 
          Natural
    Total
    %
    Value(2)
    Production
 
Core Area
  Oil (MMBbl)(1)     Gas (Bcf)     (MMBOE)     Oil(1)     (In millions)     (MBOE/d)  
 
Permian Basin
    88.1       57.8       97.7       90 %   $ 455.2       11.7  
Rocky Mountains
    49.2       203.9       83.2       59 %     548.2       27.7  
Mid-Continent
    37.2       11.7       39.1       95 %     416.2       7.2  
Gulf Coast
    3.1       41.6       10.1       31 %     105.2       5.0  
Michigan
    2.4       39.7       9.0       27 %     78.2       3.5  
                                                 
Total
    180.0       354.8       239.1       75 %   $ 1,603.0       55.1  
                                                 
 
 
(1) Oil includes natural gas liquids.
 
(2) Pre-tax PV10% may be considered a financial measure that is not calculated in accordance with generally accepted accounting principles in the United States, or GAAP, as defined by the SEC, and is derived from the standardized measure of discounted future net cash flows, which is the most directly comparable GAAP financial measure. Pre-tax PV10% is computed on the same basis as the standardized measure of discounted future net cash flows but without deducting future income taxes. As of December 31, 2008, our discounted future income taxes were $226.6 million and our standardized measure of discounted future net cash flows was $1,376.4 million. We believe pre-tax PV10% is a useful measure to investors in evaluating the relative monetary significance of our oil and gas properties. We further believe investors may utilize our pre-tax PV10% as a basis for comparison of the relative size and value of our reserves to other companies because many factors that are unique to each individual company impact the amount of future income taxes to be paid. Our management uses this measure when assessing the potential return on investment related to our oil and gas properties and acquisitions. However, pre-tax PV10% is not a substitute for the standardized measure of discounted future net cash flows. Our pre-tax PV10% and the standardized measure of discounted future net cash flows do not purport to present the fair value of our oil and natural gas reserves.
 
The following is a summary of our changes in quantities of proved oil and gas reserves for the year ended December 31, 2008:
 
                         
          Natural Gas
       
    Oil (MBbl)     (MMcf)     Total (MBOE)  
 
Balance — December 31, 2007
    196,318       326,742       250,775 (1)
Extensions and discoveries
    20,395       57,093       29,910  
Sales of minerals in place
    (3,919 )     (14,277 )     (6,298 )
Purchases of minerals in place
    513       90,329       15,568  
Production
    (12,448 )     (30,419 )     (17,517 )
Revisions to previous estimates
    (20,851 )     (74,689 )     (33,300 )(2)
                         
Balance — December 31, 2008
    180,008       354,779       239,138  
                         
 
footnotes on following page


S-2


Table of Contents

 
 
(1) If the December 31, 2007 total proved reserves had been calculated using prices as of December 31, 2008, the total proved reserves would have been 207.5 MMBOE as compared to December 31, 2008 total proved reserves of 229.9 MMBOE after adjusting 239.1 MMBOE for sales of 6.3 MMBOE and acquisitions of 15.6 MMBOE during 2008. The NYMEX prices per Bbl of oil as of December 31, 2007 and December 31, 2008 were $96.00 and $44.60, respectively. The NYMEX prices per Mcf of natural gas as of December 31, 2007 and December 31, 2008 were $7.10 and $5.63, respectively.
 
(2) Includes a 39.0 MMBOE reduction in proved reserves due to decreases in prices of oil and natural gas from December 31, 2007 to December 31, 2008.
 
Business Strategy
 
Our goal is to generate meaningful growth in both production and free cash flow by investing in oil and gas projects with attractive rates of return on capital employed. To date, we have achieved this goal through both the acquisition of reserves and continued field development in our core areas. Because of the extensive property base we have built, we are pursuing several economically attractive oil and gas opportunities to exploit and develop properties as well as explore our acreage positions for additional production growth and proved reserves. Specifically, we have focused, and plan to continue to focus, on the following:
 
Pursuing High-Return Organic Reserve Additions.  The development of large resource plays such as our Williston Basin and Piceance Basin projects has become one of our central objectives. We have assembled 125,557 gross (83,606 net) acres on the eastern side of the Williston Basin in North Dakota in an active oil development play at our Sanish field area, where the Middle Bakken reservoir is oil productive. We have drilled and completed 49 successful Bakken wells (27 operated) in our Sanish field acreage that had a combined production rate of 7,445 BOE/d during December 2008. With the acquisition of Equity Oil Company in 2004, we acquired mineral interests and federal oil and gas leases in the Piceance Basin of Colorado, where we have found the Mesaverde formation to be gas productive at our Boies Ranch and Jimmy Gulch prospect areas. Our initial drilling results in both projects have been positive. In the Piceance acreage, we have drilled and completed 23 successful wells that had a combined net production rate of 9,473 Mcf/d of natural gas during December 2008. In addition to development of our core areas, we have identified incremental opportunities in the Sanish field, Parshall field and Lewis & Clark prospect in the Williston Basin, the Sulphur Creek field — Jimmy Gulch and Wasatch prospects in the Piceance Basin and the Hatfield prospect in the Green River Basin.
 
Developing and Exploiting Existing Properties.  Our existing property base and our acquisitions over the past five years have provided us with numerous low-risk opportunities for exploitation and development drilling. As of December 31, 2008, we have identified a drilling inventory of over 1,400 gross wells that we believe will add substantial production over the next five years. Our drilling inventory consists largely of the development of our non-proved reserves on which we have spent significant time evaluating the costs and expected results. Additionally, we have several opportunities to apply and expand enhanced recovery techniques that we expect will increase proved reserves and extend the productive lives of our mature fields. In 2005, we acquired two large oil fields, the Postle field, located in the Oklahoma Panhandle, and the North Ward Estes field, located in the Permian Basin of West Texas. We have experienced and anticipate further significant production increases in these fields over the next seven years through the use of secondary and tertiary recovery techniques. In these fields, we are actively injecting water and CO2 and executing extensive re-development, drilling and completion operations, as well as enhanced gas handling and treating capability.
 
Growing Through Accretive Acquisitions.  From 2004 to 2008, we completed 13 separate acquisitions of producing properties for estimated proved reserves of 226.9 MMBOE, as of the effective dates of the acquisitions. Our experienced team of management, engineering and geoscience professionals has developed and refined an acquisition program designed to increase reserves and complement our existing properties, including identifying and evaluating acquisition opportunities, negotiating and closing purchases


S-3


Table of Contents

and managing acquired properties. We intend to selectively acquire properties complementary to our core operating areas.
 
Disciplined Financial Approach.  Our goal is to remain financially strong, yet flexible, through the prudent management of our balance sheet and active management of commodity price volatility. We have historically funded our acquisitions and growth activity through a combination of equity and debt issuances, bank borrowings and internally generated cash flow, as appropriate, to maintain our strong financial position. From time to time, we monetize non-core properties and use the net proceeds from these asset sales to repay debt under our credit agreement. For example, we established the Whiting USA Trust I, an oil and gas net profits interest trust, by offering trust units, which are traded on the New York Stock Exchange under the symbol “WHX”, to the public in April 2008, which resulted in $193.7 million in net proceeds to us that we used to repay debt. To support cash flow generation on our existing properties and help ensure expected cash flows from acquired properties, we periodically enter into derivative contracts. Typically, we use costless collars to provide an attractive base commodity price level, while maintaining the ability to benefit from improvements in commodity prices.
 
Competitive Strengths
 
We believe that our key competitive strengths lie in our balanced asset portfolio, our experienced management and technical team and our commitment to effective application of new technologies.
 
Balanced, Long-Lived Asset Base.  As of December 31, 2008, we had interests in 8,464 gross (3,558 net) productive wells across 992,392 gross (514,881 net) developed acres in our five core geographical areas. We believe this geographic mix of properties and organic drilling opportunities, combined with our continuing business strategy of acquiring and exploiting properties in these areas, presents us with multiple opportunities in executing our strategy because we are not dependent on any particular producing regions or geological formations. Our proved reserve life is approximately 13.6 years based on year-end 2008 proved reserves and 2008 production.
 
Experienced Management Team.  Our management team averages 25 years of experience in the oil and gas industry. Our personnel have extensive experience in each of our core geographical areas and in all of our operational disciplines. In addition, each of our acquisition professionals has at least 28 years of experience in the evaluation, acquisition and operational assimilation of oil and gas properties.
 
Commitment to Technology.  In each of our core operating areas, we have accumulated detailed geologic and geophysical knowledge and have developed significant technical and operational expertise. In recent years, we have developed considerable expertise in conventional and 3-D seismic imaging and interpretation. Our technical team has access to approximately 5,934 square miles of 3-D seismic data, digital well logs and other subsurface information. This data is analyzed with advanced geophysical and geological computer resources dedicated to the accurate and efficient characterization of the subsurface oil and gas reservoirs that comprise our asset base. In addition, our information systems enable us to update our production databases through daily uploads from hand held computers in the field. With the acquisition of the Postle and North Ward Estes properties, we have assembled a team of 14 professionals averaging over 20 years of expertise in managing CO2 floods. This provides us with the ability to pursue other CO2 flood targets and employ this technology to add reserves to our portfolio. This commitment to technology has increased the productivity and efficiency of our field operations and development activities.
 
Recent Developments
 
2008 Production Results, 2008 Estimated Reserves and Current Liquidity Position
 
On January 20, 2009, we announced our fourth quarter and full-year 2008 preliminary production results, estimated proved reserves as of December 31, 2008 and liquidity position as of December 31, 2008. Preliminary production for the three months ended December 31, 2008 was 5.11 MMBOE, which is an increase of 10% over third quarter 2008 production of 4.64 MMBOE. This equates to an average daily rate in the fourth quarter of 55,540 BOE/d. Preliminary production for the year ended December 31, 2008 increased


S-4


Table of Contents

19% to 17.52 MMBOE compared to 14.71 MMBOE for the year ended December 31, 2007. Our average sales prices per Bbl of oil and per Mcf of natural gas during the fourth quarter of 2008 declined to $47.37 and $4.38, respectively, compared to $108.04 and $8.65, respectively, during the third quarter of 2008. Our December 2008 average daily production was 55.14 MBOE/d.
 
As of December 31, 2008, our estimated proved reserves totaled 239.1 MMBOE. Our estimated proved reserves by core area are set forth in the table under “— About Our Company” above.
 
As of December 31, 2008, we had cash of $9.6 million, $620.0 million in borrowings and $2.8 million in letters of credit outstanding under Whiting Oil and Gas Corporation’s credit agreement and $620.0 million of senior subordinated notes outstanding. The borrowing base under Whiting Oil and Gas Corporation’s credit agreement is $900.0 million resulting in $277.2 million of available borrowing capacity at December 31, 2008.
 
2009 Capital Budget
 
On January 20, 2009, we announced our capital budget for development and exploration expenditures in 2009 to be approximately $320.4 million. More detail relating to specific items included in our 2009 budget is provided under ‘‘— 2009 Capital Budget and Major Development Areas” below.
 
Hedging Program
 
On December 23, 2008, we announced that we had completed our current hedging program. In connection with our conveyance of a term net profits interest to Whiting USA Trust I, we conveyed to Whiting USA Trust I the rights to future hedge payments we make or receive on certain of our derivative contracts from 2008 through 2012. Due to the terms of the net profits interest and our ownership of trust units, we retain 24.2% of the future economic results of such hedges. While we continue to review economically attractive opportunities with respect to hedges, the following tables summarize our current oil and natural gas hedges.
 
The following table summarizes our crude oil collars, including our 24.2% interest in Whiting USA Trust I:
 
                         
                As a Percentage
 
    Contracted
    Weighted Average
    of December
 
    Volume (Bbls
    NYMEX Price Collar
    2008 Oil
 
Collar Period
  per Month)     Range (per Bbl)     Production  
 
Year Ending December 31, 2009
    520,656     $ 57.57 — $73.95       42.5 %
Year Ending December 31, 2010
    420,524     $ 62.34 — $83.00       34.3 %
Year Ending December 31, 2011
    369,587     $ 61.68 — $86.26       30.2 %
Year Ending December 31, 2012
    338,758     $ 61.70 — $87.63       27.7 %
Eleven Months Ending November 30, 2013
    280,909     $ 60.33 — $81.46       22.9 %
 
We currently do not have any natural gas collars other than those relating to Whiting USA Trust I. The following table summarizes our 24.2% share of the Whiting USA Trust I natural gas hedges:
 
                         
    Contracted
          As a Percentage
 
    Volumes
    Weighted Average
    of December
 
    (MMBtu per
    NYMEX Price Collar
    2008 Natural
 
Collar Period
  Month)     Range (per MMBtu)     Gas Production  
 
Year Ending December 31, 2009
    48,152     $ 6.50 — $17.11       1.7 %
Year Ending December 31, 2010
    41,283     $ 6.50 — $15.06       1.4 %
Year Ending December 31, 2011
    36,376     $ 6.50 — $14.62       1.3 %
Year Ending December 31, 2012
    32,000     $ 6.50 — $14.27       1.1 %


S-5


Table of Contents

We also have the following fixed-price natural gas contracts in place:
 
                         
                As a Percentage
 
          2009 Contract
    of December
 
    Natural Gas Volumes in
    Price(1)
    2008 Natural
 
Fixed Price Contracts
  MMBtu per Month     per MMBtu     Gas Production  
 
January 2009 — May 2011
    67,000     $ 5.14       2.3 %
January 2009 — September 2012
    23,000     $ 4.56       0.8 %
 
 
(1) Annual 4% price escalation on fixed-price contracts.
 
2009 Capital Budget and Major Development Areas
 
Our previously announced capital budget of $320.4 million for development and exploration expenditures in 2009 is allocated among our major development areas as indicated in the chart below. Of our existing potential projects, we believe these present the opportunity for the highest return and most efficient use of our capital expenditures. We expect to fund these capital expenditures with net cash provided by our operating activities assuming current oil and natural gas prices. To the extent net cash provided by operating activities is higher or lower than currently anticipated, we would adjust our capital budget accordingly. The chart below does not include the development we expect to pursue with the proceeds of this offering, which is discussed under “— Prospects to be Drilled in 2009 with Offering Proceeds” below.
 
                 
        Average
     
    Average
  Net
  2009 Planned
 
    Working
  Revenue
  Capital
 
Development Area
  Interest (%)   Interest (%)   Expenditures  
            (In millions)  
 
Northern Rockies
               
Sanish Field
  74%   59%   $ 150.6  
Parshall Field
  16%   12%     12.1  
                 
Area Sub Total
          $ 162.7  
                 
CO2 Projects
               
North Ward Estes Field(1)
  100%   82%   $ 97.8  
Postle Field(1)
  97%   85%     31.5  
                 
Area Sub Total
          $ 129.3  
                 
Central Rockies
               
Flat Rock Field
  100%   79%   $ 19.1  
Sulphur Creek Field
  75%   69%     4.4  
Hatch Point Prospect
  53%   44%     3.5  
Rangely Weber Sand Unit
  5%   4%     1.4  
                 
Area Sub Total
          $ 28.4  
                 
Total
          $ 320.4  
                 
 
 
(1) 2009 planned capital expenditures at our CO2 projects include $36.9 million at North Ward Estes and $15.3 million at Postle for purchased CO2.
 
The following are descriptions of each of these major development areas:
 
Northern Rockies — Sanish and Parshall Fields
 
Sanish Field.  Our Sanish area in Mountrail County, North Dakota encompasses 125,557 gross acres (83,606 net acres). December 2008 net production in the Sanish field averaged 7.5 MBOE/d, an 832%


S-6


Table of Contents

increase from 0.8 MBOE/d in December 2007. As of January 12, 2009, we have participated in 65 wells (27 operated) that target the Bakken formation, of which 49 are producing, seven are in the process of completion and nine are being drilled. Of these operated wells, 23 were completed in 2008. We have completed and placed on production our first Bakken infill well in the Sanish field, the McNamara 42-26H. This well was drilled between two horizontal Bakken producers, the Locken 11-22H and the Liffrig 11-27H. The initial production rate at the McNamara well was 2,170 BOE/d (measured December 8, 2008), which falls between the initial production rates of the two offset wells. There was no indication of communication or interference with either of the offset wells. Based on these results, we expect to develop our leases with two 10,000-foot horizontal wells in each 1,280-acre spacing unit. We have also completed our first Three Forks horizontal well in the Sanish field, the Braaflat 21-11TFH. The initial production rate at the Braaflat well was 1,005 BOE/d (measured January 1, 2009). Production and pressure data from this well will be analyzed over several months to determine the viability of developing the Three Forks.
 
We intend to drill an additional 28 operated Bakken wells in the Sanish field during 2009, with an average working interest of 74%, five of which were being drilled at January 12, 2009. We expect an average of six drilling rigs to be working in the Sanish field during 2009. We expect our net capital expenditures in the Sanish field during 2009 to be approximately $150.6 million.
 
Parshall Field.  Immediately east of the Sanish field is the Parshall field, where we own interests in 73,760 gross acres (18,315 net acres). Our net production from the Parshall field averaged 6.7 MBOE/d in December 2008, a 341% increase from 1.5 MBOE/d in December 2007. As of January 12, 2009, we have participated in 95 Bakken wells, the majority of which are operated by EOG Resources, Inc., of which 85 are producing, four are in the process of completion and six are drilling. Of these wells, 64 were completed in 2008. We intend to participate in the drilling of an additional nine wells in the Parshall field during 2009, with an average working interest of approximately 16%. We expect our net capital expenditures in the Parshall field during 2009 to be approximately $12.1 million.
 
CO2 Projects — North Ward Estes and Postle
 
We continue to have significant development and related infrastructure activity on the Postle and North Ward Estes fields acquired in 2005, which has resulted in reserve and production increases.
 
North Ward Estes Field.  The North Ward Estes field includes six base leases with 100% working interest in approximately 58,000 gross and net acres in Ward and Winkler Counties, Texas. The North Ward Estes field is responding positively to our CO2 flood, which we initiated in May 2007. As of December 31, 2008, we were injecting 123 MMcf/d of CO2 in this field. Production from the field has increased 29% from a net 5.1 MBOE/d in December 2007 to a net 6.6 MBOE/d in December 2008. In this field, we are developing new and reactivated wells for water and CO2 injection and production purposes. Additionally, we plan to install oil, gas and water processing facilities in five phases through 2015, and we estimate that the first three phases will be substantially complete by December 2009. We expect our net capital expenditures in the North Ward Estes field during 2009 to be approximately $97.8 million, of which $36.9 million is for CO2.
 
Postle Field.  The Postle field, located in Texas County, Oklahoma, includes five producing units and one producing lease covering a total of approximately 25,600 gross (24,225 net) acres with working interests of 94% to 100%. Four of the units are currently active CO2 enhanced recovery projects. Our expansion of the CO2 flood at the Postle field continues to generate positive results. As of December 31, 2008, we were injecting 142 MMcf/d of CO2 in this field. Production from the field has increased 22% from a net 5.8 MBOE/d in December 2007 to a net 7.1 MBOE/d in December 2008. Operations are under way to expand CO2 injection into the northern part of the fourth unit, HMU, and to optimize flood patterns in the existing CO2 floods, with one drilling rig and four workover rigs in the field as of the end of 2008. These expansion projects include the restoration of shut-in wells and the drilling of new producing and injection wells. We expect our net capital expenditures in the Postle field during 2009 to be approximately $31.5 million, of which $15.3 million is for CO2.


S-7


Table of Contents

Central Rockies
 
In the Flat Rock field area in Uintah County, Utah, we have an acreage position consisting of 22,029 gross (11,533 net) acres. In this area, initial production rates of ten wells drilled in the Entrada formation by other operators have ranged from 0.7 MMcf/d to 6.1 MMcf/d. We recently completed two wells in the Entrada formation that had initial gross production rates of 4.1 MMcf/d and 9.3 MMcf/d, respectively. We are also the operator of six Entrada wells drilled by a prior operator on our acreage that had initial production rates ranging from 1.9 MMcf/d to 6.5 MMcf/d. We currently have four additional Entrada wells planned for this field for 2009 at an estimated net cost of approximately $19.1 million.
 
In the Sulphur Creek field in Rio Blanco County, Colorado in the Piceance Basin, we executed an acreage trade effective December 1, 2008 with a third party that consolidated our acreage position. As a result of such trade, we now own 8,424 gross (4,338 net) acres in the Sulphur Creek field area. We expect our net capital expenditures in our Sulphur Creek field during 2009 to be approximately $4.4 million.
 
At our Hatch Point prospect in San Juan County, Utah in the Paradox Basin, we have an exploratory horizontal well planned for 2009 in the Cane Creek zone at an estimated cost of approximately $6.5 million ($3.5 million net to us).
 
At the Rangely Weber Sand Unit in Rio Blanco County, Colorado, we own a 4.6% working interest and intend to continue participating in the development of this large field operated by Chevron that produced over 13,600 gross BOE/d during December 2008. We expect our net 2009 capital expenditures in the Rangely field to be approximately $1.4 million.
 
Prospects to be Drilled in 2009 with Offering Proceeds
 
After using the net proceeds from this offering to temporarily reduce amounts outstanding under our credit facility, we expect to use a portion of the proceeds from this offering to increase our 2009 base capital budget by approximately $123.6 million to develop incremental opportunities we have identified in the Northern and Central Rockies as a result of our drilling results during the fourth quarter of 2008 in these prospect areas. However, we may allocate this portion of the proceeds as well as the balance of the proceeds from this offering to either further develop these incremental projects or to expand the projects in our 2009 base capital budget that indicate the highest return based on drilling results through the time of such allocation. We believe that the initial wells we have drilled in these areas indicate results as attractive as the projects in our 2009 base capital budget at current oil and natural gas prices. These planned expenditures are described in more detail below:
 
                                                 
                            Average
       
                Estimated
    Average
    Net
    2009
 
                per Well
    Working
    Revenue
    Planned
 
    Completion
          Capital
    Interest
    Interest
    Capital
 
Areas
  Interval     Wells     Expenditures     (%)     (%)     Expenditures  
                (In millions)                 (In millions)  
 
Northern Rockies
                                               
Sanish Field
    Middle Bakken       12     $ 7.0       64.6 %     52.5 %   $ 54.3  
Lewis & Clark Prospect
    Three Forks       6     $ 4.0       64.0 %     52.9 %   $ 15.4  
Parshall Field
    Middle Bakken       9     $ 6.0       18.4 %     14.7 %   $ 9.9  
Central Rockies
                                               
Sulphur Creek Field —
                                               
Jimmy Gulch —
                                               
Mesaverde
    Mesaverde       9     $ 3.5       90.0 %     76.5 %   $ 28.4  
Hatfield Prospect
    Niobrara       6     $ 1.5       100.0 %     80.0 %   $ 9.0  
Sulphur Creek Field —
                                               
Wasatch
    Wasatch       6     $ 1.5       73.4 %     67.9 %   $ 6.6  
                                                 
Total
            48                             $ 123.6  
                                                 


S-8


Table of Contents

The following are descriptions of these prospect areas that we plan to drill with proceeds from this offering.
 
Northern Rockies
 
Sanish Field.  We have identified an incremental twelve wells to drill in the Sanish field in 2009 at a total estimated net capital cost of $54.3 million in addition to the wells to be drilled with the $150.6 million of capital expenditures described under “— 2009 Capital Budget and Major Development Areas” above. These additional wells would accelerate the development of this field where, as of January 12, 2009, we have participated in 65 wells (27 operated), of which 49 wells are producing from the Middle Bakken formation, seven wells are in the process of completion and nine wells are being drilled. The productive wells in the Sanish Field completed during 2008 have averaged 954 BOE/d during their first 30 days of production and 836 BOE/d during their first 60 days of production.
 
Lewis & Clark Prospect.  We have assembled 181,749 gross (111,501 net) acres in our Lewis & Clark prospect along the Bakken Shale pinch-out in the southern Williston Basin. In this area, the Upper Bakken shale is thermally mature, moderately over pressured, and has charged reservoir zones within the immediately underlying Three Forks formation. On December 13, 2008 we completed our first horizontal test well in this area, which had an initial production rate of over 1,000 BOE/d. We are currently drilling a second well and plan to drill six additional locations in 2009 based on the results of the first two wells. In this area, we can horizontally drill many of our Three Forks zone wells from existing well bores that were initially drilled for deeper objectives, which we believe reduces the cost of a new well from an estimated $7 million to an estimated $4 million per new well and a total estimated net capital cost of approximately $15.4 million.
 
Parshall Field.  We have identified an incremental nine non-operated wells to drill in the Parshall field in 2009 at a total estimated net capital cost of $9.9 million in addition to the nine non-operated wells to be drilled with the $12.1 million of capital expenditures described under “— 2009 Capital Budget and Major Development Areas” above.
 
Central Rockies
 
Sulphur Creek Field — Jimmy Gulch — Mesaverde.  The Jimmy Gulch prospect in the Sulphur Creek field area in the Piceance Basin is one square mile in area and is an eastern extension of the Boies Ranch prospect where we have drilled 34 productive wells in the Mesaverde formation as of December 31, 2008. Jimmy Gulch was tested with three wells that were producing at a combined gross rate of 7.4 MMcf/d (5.7 MMcf/d net) on January 8, 2009. We have identified another nine locations to drill in 2009 at a total estimated net capital cost of $28.4 million.
 
Hatfield Prospect.  In southern Wyoming in the Hatfield prospect area, we have a large acreage position covering over 80 square miles and encompassing 53,164 gross (31,907 net) acres. In this area, cumulative production from four vertical Niobrara wells drilled by other operators has ranged from approximately 22,000 to 124,000 barrels of oil per well. In September 2008, we drilled the Beckman Canyon 21-24D, a vertical well to test the Niobrara formation as well as a deeper zone. During drilling operations in the Niobrara at a depth of approximately 3,500 feet, oil flowed to the surface and oil shows were seen in the drill cuttings. We will conduct completion operations on this well in February 2009. In December 2008, we drilled the Artus 19-33, a horizontal Niobrara well. As of January 12, 2009, we have commenced completion operations on this well. We believe that current horizontal drilling techniques will improve recovery compared to vertical drilling used at historic wells in this area. We have identified six additional drilling locations for 2009 at a total estimated net capital cost of $9.0 million to further define and begin development of this discovery.


S-9


Table of Contents

Sulphur Creek Field — Wasatch.  We drilled our first Wasatch zone well in the Sulphur Creek field in the Piceance Basin in late 2008 and early 2009. We targeted the Wasatch based on our observation of gas shows seen while drilling through the Wasatch zone at depths of approximately 5,000 feet while drilling to the deeper Mesaverde target at a depth of approximately 10,000 feet. These results along with a study of the production data from Wasatch wells drilled in the 1970’s and 1980’s in the area of our Boies Ranch prospect provided the basis for drilling this well. Gas shows were seen while drilling, gas was indicated on well logs, and the first well penetrated approximately 50 feet of net Wasatch zone that we believe to be gas productive. Due to such results, we have identified an incremental six wells to drill in 2009 at a total estimated net capital cost of $6.6 million in addition to the wells to be drilled with the $4.4 million of capital expenditures described under “— 2009 Capital Budget and Major Development Areas” above.
 
Corporate Information
 
Our principal executive offices are located at 1700 Broadway, Suite 2300, Denver, Colorado 80290-2300, and our telephone number is (303) 837-1661.


S-10


Table of Contents

The Offering
 
The following is a brief summary of some of the terms of this offering. For a more complete description of our common stock, see “Description of Capital Stock” in the accompanying prospectus.
 
Common stock offered 8,000,000 shares
 
Shares outstanding after the offering 50,583,218 shares
 
Use of proceeds After using the net proceeds from this offering to temporarily reduce amounts outstanding under our credit facility, we expect to use a portion of the proceeds from this offering to increase our 2009 base capital budget by approximately $123.6 million to develop incremental opportunities we have identified in the Northern and Central Rockies. However, we may allocate this portion of the proceeds as well as the balance of the proceeds from this offering to either further develop these incremental projects or to expand the projects in our 2009 base capital budget that indicate the highest return based on drilling results through the time of such allocation. See “— Prospects to be Drilled in 2009 with Offering Proceeds”, “— 2009 Capital Budget and Major Development Areas” and “Use of Proceeds.”
 
Risk factors Please read “Risk Factors” and the other information in this prospectus supplement and the accompanying prospectus for a discussion of factors you should carefully consider before deciding to invest in shares of our common stock.
 
New York Stock Exchange Symbol “WLL”
 
The number of shares outstanding after the offering is based on 42,583,218 shares outstanding as of December 31, 2008. If the over-allotment option is exercised in full, we will issue and sell an additional 1,200,000 shares of our common stock.


S-11


Table of Contents

Summary Historical Financial Information
 
The following summary historical financial information as for the years ended December 31, 2005, 2006 and 2007 and as of December 31, 2005, 2006 and 2007 has been derived from, and is qualified by reference to, our audited consolidated financial statements and related notes. The following summary historical financial information for the nine months ended September 30, 2007 and 2008 and as of September 30, 2007 and 2008 has been derived from, and is qualified by reference to, our unaudited consolidated financial statements and related notes. This information is only a summary and you should read it in conjunction with our financial statements and related notes incorporated by reference in this prospectus supplement and the accompanying prospectus. The unaudited interim period financial information, in our opinion, includes all adjustments, which are normal and recurring in nature, necessary for a fair presentation for the periods shown. Results for the nine months ended September 30, 2008 are not necessarily indicative of the results to be expected for the full fiscal year.
 
                                         
          Nine Months
 
          Ended
 
    Year Ended December 31,     September 30,  
    2005     2006     2007     2007     2008  
    (In millions, except per share data)  
                      (Unaudited)  
 
Consolidated Income Statement Information:
                                       
Revenues and other income:
                                       
Oil and natural gas sales
  $ 573.2     $ 773.1     $ 809.0     $ 558.0     $ 1,102.7  
Loss on oil and natural gas hedging activities
    (33.4 )     (7.5 )     (21.2 )     (2.1 )     (112.9 )
Gain on sale of oil and gas properties
          12.1       29.7       29.7        
Amortization of deferred gain on sale
                            7.7  
Interest income and other
    0.6       1.1       1.2       0.8       0.8  
                                         
Total revenues and other income
  $ 540.4     $ 778.8     $ 818.7     $ 586.4     $ 998.3  
                                         
Costs and expenses:
                                       
Lease operating
  $ 111.6     $ 183.6     $ 208.9     $ 154.5     $ 177.9  
Production taxes
    36.1       47.1       52.4       34.9       72.0  
Depreciation, depletion and amortization
    97.6       162.8       192.8       143.2       179.6  
Exploration and impairment
    16.7       34.5       37.3       26.3       30.5  
General and administrative
    30.6       37.8       39.0       27.9       51.9  
Change in Production Participation Plan liability
    9.7       6.2       8.6       6.4       27.0  
Interest expense
    42.0       73.5       72.5       56.5       48.8  
Loss on mark-to-market derivatives
                      1.2       7.0  
                                         
Total costs and expenses
  $ 344.3     $ 545.5     $ 611.5     $ 450.9     $ 594.7  
                                         
Income before income taxes
  $ 196.1     $ 233.3     $ 207.2     $ 135.5     $ 403.6  
Income tax expense
    74.2       76.9       76.6       50.6       148.4  
                                         
Net income
  $ 121.9     $ 156.4     $ 130.6     $ 84.9     $ 255.2  
                                         
Net income per common share, basic
  $ 3.89     $ 4.26     $ 3.31     $ 2.20     $ 6.03  
                                         
Net income per common share, diluted
  $ 3.88     $ 4.25     $ 3.29     $ 2.19     $ 6.01  
                                         
Other Financial Information:
                                       
Net cash provided by operating activities
  $ 330.2     $ 411.2     $ 394.0     $ 272.6     $ 611.5  
Capital expenditures
  $ 1,126.9     $ 552.0     $ 519.6     $ 370.5     $ 1,051.6  
EBITDA(1)
  $ 335.7     $ 469.6     $ 472.5     $ 335.2     $ 632.0  
 


S-12


Table of Contents

                                         
    As of December 31,     As of September 30,  
    2005     2006     2007     2007     2008  
                (In millions)     (Unaudited)  
 
Consolidated Balance Sheet Information:
                                       
Total assets
  $ 2,235.2     $ 2,585.4     $ 2,952.0     $ 2,811.0     $ 3,835.1  
Total debt
  $ 875.1     $ 995.4     $ 868.2     $ 836.7     $ 1,118.6  
Stockholders’ equity
  $ 997.9     $ 1,186.7     $ 1,490.8     $ 1,472.9     $ 1,779.4  
 
 
(1) We define EBITDA as earnings before interest, taxes, depreciation, depletion and amortization. EBITDA is not a measure of performance calculated in accordance with generally accepted accounting principles in the United States, or GAAP. Although not prescribed under GAAP, we believe the presentation of EBITDA is relevant and useful because it helps our investors to understand our operating performance and makes it easier to compare our results with other companies that have different financing and capital structures or tax rates. EBITDA should not be considered in isolation of, or as a substitute for, net income as an indicator of operating performance or cash flows from operating activities as a measure of liquidity. EBITDA, as we calculate it, may not be comparable to EBITDA measures reported by other companies. In addition, EBITDA does not represent funds available for discretionary use.
 
The following table presents a reconciliation of our consolidated net income to our consolidated EBITDA for the periods presented:
 
                                         
          Nine Months Ended
 
    Year Ended December 31,     September 30,  
    2005     2006     2007     2007     2008  
                (In millions)              
 
Net income
  $ 121.9     $ 156.4     $ 130.6     $ 84.9     $ 255.2  
Income tax expense
    74.2       76.9       76.6       50.6       148.4  
Interest expense
    42.0       73.5       72.5       56.5       48.8  
Depreciation, depletion and amortization
    97.6       162.8       192.8       143.2       179.6  
                                         
EBITDA
  $ 335.7     $ 469.6     $ 472.5     $ 335.2     $ 632.0  
                                         

S-13


Table of Contents

Summary Historical Reserve and Operating Data
 
The following tables present summary information regarding our estimated net proved oil and natural gas reserves as of December 31, 2006, 2007 and 2008 and our historical operating data for the years ended December 31, 2005, 2006 and 2007. All calculations of estimated net proved reserves have been made in accordance with the rules and regulations of the SEC and, except as otherwise indicated, give no effect to federal or state income taxes.
 
                         
    As of December 31,  
    2006     2007     2008  
 
Reserve Data:
                       
Total estimated proved developed reserves:
                       
Oil (MMBbls)
    122.5       127.3       121.0  
Natural gas (Bcf)
    226.5       237.0       229.2  
Total (MMBOE)
    160.2       166.8       159.2  
Total estimated proved reserves:
                       
Oil (MMBbls)
    195.0       196.3       180.0  
Natural gas (Bcf)
    318.9       326.7       354.8  
Total (MMBOE)
    248.1       250.8       239.1  
Pre-tax PV10% value (in millions)(1)(2)
  $ 3,352.2     $ 5,858.3     $ 1,603.0  
Standardized measure of discounted future net cash flows (in millions)(1)(3)
  $ 2,392.2     $ 4,011.7     $ 1,376.4  
 
 
(1) The December 31, 2006 amount was calculated using a period end average realized oil price of $54.81 per Bbl and a period end average realized natural gas price of $5.41 per Mcf, the December 31, 2007 amount was calculated using a period end average realized oil price of $88.62 per Bbl and a period end average realized natural gas price of $6.31 per Mcf and the December 31, 2008 amount was calculated using a period end average realized oil price of $44.60 per Bbl and a period end average realized natural gas price of $5.63 per Mcf.
 
(2) Pre-tax PV10% may be considered a non-GAAP financial measure as defined by the SEC and is derived from the standardized measure of discounted future net cash flows, which is the most directly comparable GAAP financial measure. Pre-tax PV10% is computed on the same basis as the standardized measure of discounted future net cash flows but without deducting future income taxes. Our discounted future income taxes were $960.0 million as of December 31, 2006, $1,846.6 million as of December 31, 2007 and $226.6 million as of December 31, 2008. We believe pre-tax PV10% is a useful measure to investors in evaluating the relative monetary significance of our oil and gas properties. We further believe investors may utilize our pre-tax PV10% as a basis for comparison of the relative size and value of our reserves to other companies because many factors that are unique to each individual company impact the amount of future income taxes to be paid. Our management uses this measure when assessing the potential return on investment related to our oil and gas properties and acquisitions. However, pre-tax PV10% is not a substitute for the standardized measure of discounted future net cash flows. Our pre-tax PV10% and the standardized measure of discounted future net cash flows do not purport to present the fair value of our oil and natural gas reserves.
 
(3) The standardized measure of discounted future net cash flows, which reflects the after-tax present value of discounted future net cash flows, relating to proved oil and natural gas reserves were prepared in accordance with the provisions of Statement of Financial Accounting Standards No. 69. Future cash inflows were computed by applying prices at year end to estimated future production. Future production and development costs are computed by estimating the expenditures to be incurred in developing and producing the proved oil and natural gas reserves at year end, based on year-end costs and assuming continuation of existing economic conditions. Future net cash flows are discounted at a rate of 10% annually to derive the standardized measure of discounted future net cash flows. This calculation procedure does not necessarily result in an estimate of the fair market value or the present value of our oil and gas properties.


S-14


Table of Contents

 
                                         
          Nine Months Ended
 
    Year Ended December 31,     September 30,  
    2005     2006     2007     2007     2008  
 
Operating Data:
                                       
Net Production:
                                       
Oil (MMBbls)
    7.0       9.8       9.6       7.1       8.7  
Natural gas (Bcf)
    30.3       32.1       30.8       23.3       22.4  
Total production (MMBOE)
    12.1       15.2       14.7       11.0       12.4  
Net Sales (in millions)(1):
                                       
Oil
  $ 360.4     $ 561.2     $ 618.5     $ 414.8     $ 904.1  
Natural gas
  $ 212.8     $ 211.9     $ 190.5     $ 143.2     $ 198.6  
                                         
Total oil and natural gas
  $ 573.2     $ 773.1     $ 809.0     $ 558.0     $ 1,102.7  
Average sales prices:
                                       
Oil (per Bbl)
  $ 51.26     $ 57.27     $ 64.57     $ 58.37     $ 104.21  
Effect of oil hedges on average price (per Bbl)
  $ (2.72 )   $ (0.95 )   $ (2.21 )   $ (0.29 )   $ (13.01 )
                                         
Oil net of hedging (per Bbl)
  $ 48.54     $ 56.32     $ 62.36     $ 58.08     $ 91.20  
Average NYMEX price
  $ 56.61     $ 66.25     $ 72.30     $ 66.12     $ 113.38  
Natural gas (per Mcf)
  $ 7.03     $ 6.59     $ 6.19     $ 6.14     $ 8.87  
Effect of natural gas hedges on average price (per Mcf)
  $ (0.47 )   $ 0.06     $     $     $  
                                         
Natural gas net of hedging (per Mcf)
  $ 6.56     $ 6.65     $ 6.19     $ 6.14     $ 8.87  
Average NYMEX price
  $ 8.64     $ 7.23     $ 6.86     $ 6.83     $ 9.75  
Cost and expenses (per BOE):
                                       
Lease operating expenses
  $ 9.24     $ 12.12     $ 14.20     $ 14.05     $ 14.33  
Production taxes
  $ 2.99     $ 3.11     $ 3.56     $ 3.17     $ 5.80  
Depreciation, depletion and amortization expenses
  $ 8.08     $ 10.74     $ 13.11     $ 13.02     $ 14.47  
General and administrative expenses
  $ 2.53     $ 2.49     $ 2.66     $ 2.54     $ 4.18  
 
 
(1) Before consideration of hedging transactions


S-15


Table of Contents

 
RISK FACTORS
 
You should carefully consider each of the risks described below, together with all of the other information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus, before deciding to invest in shares of our common stock. If any of the following risks develop into actual events, our business, financial condition or results of operations could be materially adversely affected and you may lose all or part of your investment.
 
Risks Relating to the Oil and Gas Industry and Our Business
 
Oil and natural gas prices are very volatile. A substantial or extended decline in oil and natural gas prices may adversely affect our business, financial condition, results of operations or cash flows.
 
The oil and gas markets are very volatile, and we cannot predict future oil and natural gas prices. The price we receive for our oil and natural gas production heavily influences our revenue, profitability, access to capital and future rate of growth. The prices we receive for our production and the levels of our production depend on numerous factors beyond our control. These factors include, but are not limited to, the following:
 
  •      changes in global supply and demand for oil and gas;
 
  •      the actions of the Organization of Petroleum Exporting Countries;
 
  •      the price and quantity of imports of foreign oil and gas;
 
  •      political and economic conditions, including embargoes, in oil-producing countries or affecting other oil-producing activity;
 
  •      the level of global oil and gas exploration and production activity;
 
  •      the level of global oil and gas inventories;
 
  •      weather conditions;
 
  •      technological advances affecting energy consumption;
 
  •      domestic and foreign governmental regulations;
 
  •      proximity and capacity of oil and gas pipelines and other transportation facilities;
 
  •      the price and availability of competitors’ supplies of oil and gas in captive market areas; and
 
  •      the price and availability of alternative fuels.
 
Furthermore, the recent worldwide financial and credit crisis has reduced the availability of liquidity and credit to fund the continuation and expansion of industrial business operations worldwide. The shortage of liquidity and credit combined with recent substantial losses in worldwide equity markets has lead to a worldwide economic recession. The slowdown in economic activity caused by such recession has reduced worldwide demand for energy and resulted in lower oil and natural gas prices. Oil prices declined from record levels in early July 2008 of over $140 per Bbl to below $40 per Bbl in December 2008, while natural gas prices have declined from over $13 per Mcf to below $6 per Mcf over the same period. In addition, the forecasted prices for 2009 have also declined.
 
Lower oil and natural gas prices may not only decrease our revenues on a per unit basis but also may reduce the amount of oil and natural gas that we can produce economically and therefore potentially lower our reserve bookings. A substantial or extended decline in oil or natural gas prices may materially and adversely affect our future business, financial condition, results of operations, liquidity or ability to finance planned capital expenditures. For example, we expect to fund our 2009 base capital budget of $320.4 million through net cash provided by our operating activities. To the extent commodity prices received from production are insufficient to fund this budget, we will be required to reduce capital spending or borrow any such shortfall. Lower oil and natural gas prices may also reduce the amount of our borrowing base under our credit agreement, which is determined at the discretion of the lenders based on the collateral value of our proved


S-16


Table of Contents

reserves that have been mortgaged to the lenders, and is subject to regular redeterminations on May 1 and November 1 of each year, as well as special redeterminations described in the credit agreement.
 
The global financial crisis may have impacts on our business and financial condition that we currently cannot predict.
 
The continued credit crisis and related turmoil in the global financial system may have an impact on our business and our financial condition, and we may face challenges if conditions in the financial markets do not improve. Our ability to access the capital markets may be restricted at a time when we would like, or need, to raise financing, which could have an impact on our flexibility to react to changing economic and business conditions. The economic situation could have an impact on our lenders or customers, causing them to fail to meet their obligations to us. Additionally, market conditions could have an impact on our commodity hedging arrangements if our counterparties are unable to perform their obligations or seek bankruptcy protection.
 
Drilling for and producing oil and natural gas are high risk activities with many uncertainties that could adversely affect our business, financial condition or results of operations.
 
Our future success will depend on the success of our development, exploitation, production and exploration activities. Our oil and natural gas exploration and production activities are subject to numerous risks beyond our control, including the risk that drilling will not result in commercially viable oil or natural gas production. Our decisions to purchase, explore, develop or otherwise exploit prospects or properties will depend in part on the evaluation of data obtained through geophysical and geological analyses, production data and engineering studies, the results of which are often inconclusive or subject to varying interpretations. Please read “— Reserve estimates depend on many assumptions that may turn out to be inaccurate . . .” later in this prospectus supplement for a discussion of the uncertainty involved in these processes. Our cost of drilling, completing and operating wells is often uncertain before drilling commences. Overruns in budgeted expenditures are common risks that can make a particular project uneconomical. Further, many factors may curtail, delay or cancel drilling, including the following:
 
  •      delays imposed by or resulting from compliance with regulatory requirements;
 
  •      pressure or irregularities in geological formations;
 
  •      shortages of or delays in obtaining equipment, including drilling rigs, CO2 and qualified personnel;
 
  •      equipment failures or accidents;
 
  •      adverse weather conditions, such as hurricanes and storms;
 
  •      reductions in oil and natural gas prices; and
 
  •      title problems.
 
Prospects that we decide to drill may not yield oil or gas in commercially viable quantities.
 
We describe some of our current prospects and our plans to explore those prospects in this prospectus supplement. A prospect is a property on which we have identified what our geoscientists believe, based on available seismic and geological information, to be indications of oil or gas. Our prospects are in various stages of evaluation, ranging from a prospect which is ready to drill to a prospect that will require substantial additional seismic data processing and interpretation. There is no way to predict in advance of drilling and testing whether any particular prospect will yield oil or gas in sufficient quantities to recover drilling or completion costs or to be economically viable. The use of seismic data and other technologies and the study of producing fields in the same area will not enable us to know conclusively prior to drilling whether oil or gas will be present or, if present, whether oil or gas will be present in commercial quantities. In addition, because of the wide variance that results from different equipment used to test the wells, initial flowrates may not be indicative of sufficient oil or gas quantities in a particular field. The analogies we draw from available


S-17


Table of Contents

data from other wells, more fully explored prospects or producing fields may not be applicable to our drilling prospects. We may terminate our drilling program for a prospect if results do not merit further investment.
 
Our identified drilling locations are scheduled out over several years, making them susceptible to uncertainties that could materially alter the occurrence or timing of their drilling.
 
We have specifically identified and scheduled drilling locations as an estimation of our future multi-year drilling activities on our existing acreage including the locations included in our budget for 2009. As of December 31, 2008, we had identified a drilling inventory of over 1,400 gross drilling locations. These scheduled drilling locations represent a significant part of our growth strategy. Our ability to drill and develop these locations depends on a number of uncertainties, including oil and natural gas prices, the availability of capital, including our ability to fund our 2009 base capital budget of $320.4 million through net cash provided by our operating activities, costs of oil field goods and services, drilling results, regulatory approvals and other factors. Because of these uncertainties, we do not know if the numerous potential drilling locations we have identified will ever be drilled or if we will be able to produce oil or gas from these or any other potential drilling locations. As such, our actual drilling activities may materially differ from those presently identified, which could adversely affect our business.
 
We have been an early entrant into new or emerging plays; as a result, our drilling results in these areas are uncertain, and the value of our undeveloped acreage will decline and we may incur impairment charges if drilling results are unsuccessful.
 
While our costs to acquire undeveloped acreage in new or emerging plays have generally been less than those of later entrants into a developing play, our drilling results in these areas are more uncertain than drilling results in areas that are developed and producing. Since new or emerging plays have limited or no production history, we are unable to use past drilling results in those areas to help predict our future drilling results. Therefore, our cost of drilling, completing and operating wells in these areas may be higher than initially expected, and the value of our undeveloped acreage will decline if drilling results are unsuccessful. Furthermore, if drilling results are unsuccessful, we may be required to write down the carrying value of our undeveloped acreage in new or emerging plays. For the fourth quarter of 2008, we expect to record a $10.9 million non-cash impairment charge to income to write down a portion of our $18.4 million cost basis in unproved properties in the central Utah Hingeline play. We may also incur such impairment charges in the future, which could have a material adverse effect on our results of operations in the period taken.
 
Our use of enhanced recovery methods creates uncertainties that could adversely affect our results of operations and financial condition.
 
One of our business strategies is to commercially develop oil reservoirs using enhanced recovery technologies. For example, we inject water and CO2 into formations on some of our properties to increase the production of oil and natural gas. The additional production and reserves attributable to the use of these enhanced recovery methods are inherently difficult to predict. If our enhanced recovery programs do not allow for the extraction of oil and gas in the manner or to the extent that we anticipate, our future results of operations and financial condition could be materially adversely affected. Additionally, our ability to utilize CO2 as an enhanced recovery technique is subject to our ability to obtain sufficient quantities of CO2. Our CO2 contracts permit the suppliers to reduce the amount of CO2 they provide to us in certain circumstances. If this occurs, we may not have sufficient CO2 to produce oil and natural gas in the manner or to the extent that we anticipate. These contracts are also structured as “take-or-pay” arrangements, which require us to continue to make payments even if we decide to terminate or reduce our use of CO2 as part of our enhanced recovery techniques.
 
The development of the proved undeveloped reserves in the North Ward Estes and Postle fields may take longer and may require higher levels of capital expenditures than we currently anticipate.
 
As of December 31, 2008, undeveloped reserves comprised 46.5% of the North Ward Estes field’s total estimated proved reserves and 16.8% of Postle field’s estimated total proved reserves. To fully develop


S-18


Table of Contents

these reserves, we expect to incur total future development costs of $410.1 million at the North Ward Estes field and $84.5 million at the Postle field. During 2007 and 2006, the estimated future capital expenditures necessary to develop the proved reserves at the North Ward Estes field and Postle field increased substantially. The increases were due to several factors, including equipment and service cost inflation, higher CO2 unit costs and volumes, higher costs associated with the expanded scope of previously identified projects, as well as new projects identified during 2006. Together, these fields encompass 59% of our estimated total future development costs related to proved reserves. Development of these reserves may take longer and require higher levels of capital expenditures than we currently anticipate. In addition, the development of these reserves will require the use of enhanced recovery techniques, including water flood and CO2 injection installations, the success of which is less predictable than traditional development techniques. Therefore, ultimate recoveries from these fields may not match current expectations.
 
If oil and natural gas prices decrease, we may be required to take write-downs of the carrying values of our oil and gas properties.
 
Accounting rules require that we review periodically the carrying value of our oil and gas properties for possible impairment. Based on specific market factors and circumstances at the time of prospective impairment reviews, and the continuing evaluation of development plans, production data, economics and other factors, we may be required to write down the carrying value of our oil and gas properties. A write-down constitutes a non-cash charge to earnings. We may incur impairment charges in the future, which could have a material adverse effect on our results of operations in the period taken.
 
Reserve estimates depend on many assumptions that may turn out to be inaccurate. Any material inaccuracies in these reserve estimates or underlying assumptions will materially affect the quantities and present value of our reserves.
 
The process of estimating oil and natural gas reserves is complex. It requires interpretations of available technical data and many assumptions, including assumptions relating to economic factors. Any significant inaccuracies in these interpretations or assumptions could materially affect the estimated quantities and present value of reserves referred to in this prospectus supplement.
 
In order to prepare our estimates, we must project production rates and timing of development expenditures. We must also analyze available geological, geophysical, production and engineering data. The extent, quality and reliability of this data can vary. The process also requires economic assumptions about matters such as oil and natural gas prices, drilling and operating expenses, capital expenditures, taxes and availability of funds. Therefore, estimates of oil and natural gas reserves are inherently imprecise.
 
Actual future production, oil and natural gas prices, revenues, taxes, exploration and development expenditures, operating expenses and quantities of recoverable oil and natural gas reserves most likely will vary from our estimates. Any significant variance could materially affect the estimated quantities and present value of reserves referred to in this prospectus supplement. In addition, we may adjust estimates of proved reserves to reflect production history, results of exploration and development, prevailing oil and natural gas prices and other factors, many of which are beyond our control.
 
You should not assume that the present value of future net revenues from our proved reserves, as referred to in this prospectus supplement, is the current market value of our estimated oil and natural gas reserves. In accordance with SEC requirements, we generally base the estimated discounted future net cash flows from our proved reserves on prices and costs on the date of the estimate. Actual future prices and costs may differ materially from those used in the present value estimate. If natural gas prices decline by $0.10 per Mcf, then the standardized measure of discounted future net cash flows of our estimated proved reserves as of December 31, 2008 would have decreased from $1,376.4 million to $1,366.0 million. If oil prices decline by $1.00 per Bbl, then the standardized measure of discounted future net cash flows of our estimated proved reserves as of December 31, 2008 would have decreased from $1,376.4 million to $1,326.1 million.


S-19


Table of Contents

Our debt level and the covenants in the agreements governing our debt could negatively impact our financial condition, results of operations, cash flows and business prospects.
 
As of December 31, 2008, we had $620.0 million in borrowings and $2.8 million in letters of credit outstanding under Whiting Oil and Gas Corporation’s credit agreement with $277.2 million of available borrowing capacity, as well as $620.0 million of senior subordinated notes outstanding. We are permitted to incur additional indebtedness, provided we meet certain requirements in the indentures governing our senior subordinated notes and Whiting Oil and Gas Corporation’s credit agreement.
 
Our level of indebtedness and the covenants contained in the agreements governing our debt could have important consequences for our operations, including:
 
  •      requiring us to dedicate a substantial portion of our cash flow from operations to required payments on debt, thereby reducing the availability of cash flow for working capital, capital expenditures and other general business activities;
 
  •      limiting our ability to obtain additional financing in the future for working capital, capital expenditures, acquisitions and general corporate and other activities;
 
  •      limiting our flexibility in planning for, or reacting to, changes in our business and the industry in which we operate;
 
  •      placing us at a competitive disadvantage relative to other less leveraged competitors; and
 
  •      making us vulnerable to increases in interest rates, because debt under Whiting Oil and Gas Corporation’s credit agreement may be at variable rates.
 
We may be required to repay all or a portion of our debt on an accelerated basis in certain circumstances. If we fail to comply with the covenants and other restrictions in the agreements governing our debt, it could lead to an event of default and the acceleration of our repayment of outstanding debt. Our ability to comply with these covenants and other restrictions may be affected by events beyond our control, including prevailing economic and financial conditions. Moreover, the borrowing base limitation on Whiting Oil and Gas Corporation’s credit agreement is periodically redetermined based on an evaluation of our reserves. Upon a redetermination, if borrowings in excess of the revised borrowing capacity were outstanding, we could be forced to repay a portion of our debt under the credit agreement.
 
We may not have sufficient funds to make such repayments. If we are unable to repay our debt out of cash on hand, we could attempt to refinance such debt, sell assets or repay such debt with the proceeds from an equity offering. We may not be able to generate sufficient cash flow to pay the interest on our debt or future borrowings, and equity financings or proceeds from the sale of assets may not be available to pay or refinance such debt. The terms of our debt, including Whiting Oil and Gas Corporation’s credit agreement, may also prohibit us from taking such actions. Factors that will affect our ability to raise cash through an offering of our capital stock, a refinancing of our debt or a sale of assets include financial market conditions and our market value and operating performance at the time of such offering or other financing. We may not be able to successfully complete any such offering, refinancing or sale of assets.
 
The instruments governing our indebtedness contain various covenants limiting the discretion of our management in operating our business.
 
The indentures governing our senior subordinated notes and Whiting Oil and Gas Corporation’s credit agreement contain various restrictive covenants that may potentially limit our management’s discretion in certain respects. In particular, these agreements will limit our and our subsidiaries’ ability to, among other things:
 
  •      pay dividends on, redeem or repurchase our capital stock or redeem or repurchase our subordinated debt;
 
  •      make loans to others;


S-20


Table of Contents

 
  •      make investments;
 
  •      incur additional indebtedness or issue preferred stock;
 
  •      create certain liens;
 
  •      sell assets;
 
  •      enter into agreements that restrict dividends or other payments from our restricted subsidiaries to us;
 
  •      consolidate, merge or transfer all or substantially all of the assets of us and our restricted subsidiaries taken as a whole;
 
  •      engage in transactions with affiliates;
 
  •      enter into hedging contracts;
 
  •      create unrestricted subsidiaries; and
 
  •      enter into sale and leaseback transactions.
 
In addition, Whiting Oil and Gas Corporation’s credit agreement requires us to maintain a debt to EBITDAX ratio (as defined in the credit agreement) of less than 3.5 to 1 and a working capital ratio of greater than 1 to 1. Also, the indentures under which we issued our senior subordinated notes restrict us from incurring additional indebtedness, subject to certain exceptions, unless our fixed charge coverage ratio (as defined in the indentures) is at least 2.0 to 1. If we were in violation of this covenant, then we may not be able to incur additional indebtedness, including under Whiting Oil and Gas Corporation’s credit agreement.
 
If we fail to comply with the restrictions in the indentures governing our senior subordinated notes or Whiting Oil and Gas Corporation’s credit agreement or any other subsequent financing agreements, a default may allow the creditors, if the agreements so provide, to accelerate the related indebtedness as well as any other indebtedness to which a cross-acceleration or cross-default provision applies. In addition, lenders may be able to terminate any commitments they had made to make available further funds.
 
Our exploration and development operations require substantial capital, and we may be unable to obtain needed capital or financing on satisfactory terms, which could lead to a loss of properties and a decline in our oil and natural gas reserves.
 
The oil and gas industry is capital intensive. We make and expect to continue to make substantial capital expenditures in our business and operations for the exploration, development, production and acquisition of oil and natural gas reserves. To date, we have financed capital expenditures primarily with bank borrowings and cash generated by operations. We intend to finance our future capital expenditures with cash flow from operations and our existing financing arrangements. Our cash flow from operations and access to capital is subject to a number of variables, including:
 
  •      our proved reserves;
 
  •      the level of oil and natural gas we are able to produce from existing wells;
 
  •      the prices at which oil and natural gas are sold; and
 
  •      our ability to acquire, locate and produce new reserves.
 
If our revenues or the borrowing base under our bank credit agreement decreases as a result of lower oil and natural gas prices, operating difficulties, declines in reserves or for any other reason, then we may have limited ability to obtain the capital necessary to sustain our operations at current levels. We may, from time to time, need to seek additional financing. There can be no assurance as to the availability or terms of any additional financing.
 
If additional capital is needed, we may not be able to obtain debt or equity financing on terms favorable to us, or at all. If cash generated by operations or available under our revolving credit facility is not


S-21


Table of Contents

sufficient to meet our capital requirements, the failure to obtain additional financing could result in a curtailment of our operations relating to the exploration and development of our prospects, which in turn could lead to a possible loss of properties and a decline in our oil and natural gas reserves.
 
Our acquisition activities may not be successful.
 
As part of our growth strategy, we have made and may continue to make acquisitions of businesses and properties. However, suitable acquisition candidates may not continue to be available on terms and conditions we find acceptable, and acquisitions pose substantial risks to our business, financial condition and results of operations. In pursuing acquisitions, we compete with other companies, many of which have greater financial and other resources to acquire attractive companies and properties. The following are some of the risks associated with acquisitions, including any completed or future acquisitions:
 
  •      some of the acquired businesses or properties may not produce revenues, reserves, earnings or cash flow at anticipated levels;
 
  •      we may assume liabilities that were not disclosed to us or that exceed our estimates;
 
  •      we may be unable to integrate acquired businesses successfully and realize anticipated economic, operational and other benefits in a timely manner, which could result in substantial costs and delays or other operational, technical or financial problems;
 
  •      acquisitions could disrupt our ongoing business, distract management, divert resources and make it difficult to maintain our current business standards, controls and procedures; and
 
  •      we may issue additional debt securities or equity related to future acquisitions.
 
Substantial acquisitions or other transactions could require significant external capital and could change our risk and property profile.
 
In order to finance acquisitions of additional producing properties, we may need to alter or increase our capitalization substantially through the issuance of debt or equity securities, the sale of production payments or other means. These changes in capitalization may significantly affect our risk profile. Additionally, significant acquisitions or other transactions can change the character of our operations and business. The character of the new properties may be substantially different in operating or geological characteristics or geographic location than our existing properties. Furthermore, we may not be able to obtain external funding for future acquisitions or other transactions or to obtain external funding on terms acceptable to us.
 
Properties that we acquire may not produce as projected, and we may be unable to identify liabilities associated with the properties or obtain protection from sellers against them.
 
Our business strategy includes a continuing acquisition program. From 2004 to 2008, we completed 13 separate acquisitions of producing properties for estimated proved reserves as of the effective dates of the acquisitions of 226.9 MMBOE. The successful acquisition of producing properties requires assessments of many factors, which are inherently inexact and may be inaccurate, including the following:
 
  •      the amount of recoverable reserves;
 
  •      future oil and natural gas prices;
 
  •      estimates of operating costs;
 
  •      estimates of future development costs;
 
  •      timing of future development costs;
 
  •      estimates of the costs and timing of plugging and abandonment; and
 
  •      potential environmental and other liabilities.


S-22


Table of Contents

 
Our assessment will not reveal all existing or potential problems, nor will it permit us to become familiar enough with the properties to assess fully their capabilities and deficiencies. In the course of our due diligence, we may not inspect every well, platform or pipeline. Inspections may not reveal structural and environmental problems, such as pipeline corrosion or groundwater contamination, when they are made. We may not be able to obtain contractual indemnities from the seller for liabilities that it created. We may be required to assume the risk of the physical condition of the properties in addition to the risk that the properties may not perform in accordance with our expectations.
 
Seasonal weather conditions and lease stipulations adversely affect our ability to conduct drilling activities in some of the areas where we operate.
 
Oil and gas operations in the Rocky Mountains are adversely affected by seasonal weather conditions and lease stipulations designed to protect various wildlife. In certain areas drilling and other oil and gas activities can only be conducted during the spring and summer months. This limits our ability to operate in those areas and can intensify competition during those months for drilling rigs, oil field equipment, services, supplies and qualified personnel, which may lead to periodic shortages. Resulting shortages or high costs could delay our operations and materially increase our operating and capital costs.
 
The differential between the NYMEX or other benchmark price of oil and natural gas and the wellhead price we receive could have a material adverse effect on our results of operations, financial condition and cash flows.
 
The prices that we receive for our oil and natural gas production generally trade at a discount to the relevant benchmark prices, such as NYMEX, that are used for calculating hedge positions. The difference between the benchmark price and the price we receive is called a differential. We cannot accurately predict oil and natural gas differentials. Increases in the differential between the benchmark price for oil and natural gas and the wellhead price we receive could have a material adverse effect on our results of operations, financial condition and cash flows.
 
We may incur substantial losses and be subject to substantial liability claims as a result of our oil and gas operations.
 
We are not insured against all risks. Losses and liabilities arising from uninsured and underinsured events could materially and adversely affect our business, financial condition or results of operations. Our oil and natural gas exploration and production activities are subject to all of the operating risks associated with drilling for and producing oil and natural gas, including the possibility of:
 
  •      environmental hazards, such as uncontrollable flows of oil, gas, brine, well fluids, toxic gas or other pollution into the environment, including groundwater and shoreline contamination;
 
  •      abnormally pressured formations;
 
  •      mechanical difficulties, such as stuck oil field drilling and service tools and casing collapse;
 
  •      fires and explosions;
 
  •      personal injuries and death; and
 
  •      natural disasters.
 
Any of these risks could adversely affect our ability to conduct operations or result in substantial losses to our company. We may elect not to obtain insurance if we believe that the cost of available insurance is excessive relative to the risks presented. In addition, pollution and environmental risks generally are not fully insurable. If a significant accident or other event occurs and is not fully covered by insurance, then it could adversely affect us.


S-23


Table of Contents

We have limited control over activities on properties we do not operate, which could reduce our production and revenues.
 
If we do not operate the properties in which we own an interest, we do not have control over normal operating procedures, expenditures or future development of underlying properties. The failure of an operator of our wells to adequately perform operations or an operator’s breach of the applicable agreements could reduce our production and revenues. The success and timing of our drilling and development activities on properties operated by others therefore depends upon a number of factors outside of our control, including the operator’s timing and amount of capital expenditures, expertise and financial resources, inclusion of other participants in drilling wells, and use of technology. Because we do not have a majority interest in most wells we do not operate, we may not be in a position to remove the operator in the event of poor performance.
 
Our use of 3-D seismic data is subject to interpretation and may not accurately identify the presence of oil and gas, which could adversely affect the results of our drilling operations.
 
Even when properly used and interpreted, 3-D seismic data and visualization techniques are only tools used to assist geoscientists in identifying subsurface structures and hydrocarbon indicators and do not enable the interpreter to know whether hydrocarbons are, in fact, present in those structures. In addition, the use of 3-D seismic and other advanced technologies requires greater predrilling expenditures than traditional drilling strategies, and we could incur losses as a result of such expenditures. Thus, some of our drilling activities may not be successful or economical, and our overall drilling success rate or our drilling success rate for activities in a particular area could decline. We often gather 3-D seismic data over large areas. Our interpretation of seismic data delineates for us those portions of an area that we believe are desirable for drilling. Therefore, we may choose not to acquire option or lease rights prior to acquiring seismic data, and in many cases, we may identify hydrocarbon indicators before seeking option or lease rights in the location. If we are not able to lease those locations on acceptable terms, it would result in our having made substantial expenditures to acquire and analyze 3-D seismic data without having an opportunity to attempt to benefit from those expenditures.
 
Market conditions or operational impediments may hinder our access to oil and gas markets or delay our production.
 
In connection with our continued development of oil and gas properties, we may be disproportionately exposed to the impact of delays or interruptions of production from wells in these properties, caused by transportation capacity constraints, curtailment of production or the interruption of transporting oil and gas volumes produced. In addition, market conditions or a lack of satisfactory oil and gas transportation arrangements may hinder our access to oil and gas markets or delay our production. The availability of a ready market for our oil and natural gas production depends on a number of factors, including the demand for and supply of oil and natural gas and the proximity of reserves to pipelines and terminal facilities. Our ability to market our production depends substantially on the availability and capacity of gathering systems, pipelines and processing facilities owned and operated by third-parties. Additionally, entering into arrangements for these services exposes us to the risk that third parties will default on their obligations under such arrangements. Our failure to obtain such services on acceptable terms or the default by a third party on their obligation to provide such services could materially harm our business. We may be required to shut in wells for a lack of a market or because access to gas pipelines, gathering systems or processing facilities may be limited or unavailable. If that were to occur, then we would be unable to realize revenue from those wells until production arrangements were made to deliver the production to market.
 
We are subject to complex laws that can affect the cost, manner or feasibility of doing business.
 
Exploration, development, production and sale of oil and natural gas are subject to extensive federal, state, local and international regulation. We may be required to make large expenditures to comply with governmental regulations. Matters subject to regulation include:
 
  •      discharge permits for drilling operations;


S-24


Table of Contents

 
  •      drilling bonds;
 
  •      reports concerning operations;
 
  •      the spacing of wells;
 
  •      unitization and pooling of properties; and
 
  •      taxation.
 
Under these laws, we could be liable for personal injuries, property damage and other damages. Failure to comply with these laws also may result in the suspension or termination of our operations and subject us to administrative, civil and criminal penalties. Moreover, these laws could change in ways that could substantially increase our costs. Any such liabilities, penalties, suspensions, terminations or regulatory changes could materially adversely affect our financial condition and results of operations.
 
Our operations may incur substantial liabilities to comply with environmental laws and regulations.
 
Our oil and gas operations are subject to stringent federal, state and local laws and regulations relating to the release or disposal of materials into the environment or otherwise relating to environmental protection. These laws and regulations may require the acquisition of a permit before drilling commences; restrict the types, quantities, and concentration of materials that can be released into the environment in connection with drilling and production activities; limit or prohibit drilling activities on certain lands lying within wilderness, wetlands, and other protected areas; and impose substantial liabilities for pollution resulting from our operations. Failure to comply with these laws and regulations may result in the assessment of administrative, civil, and criminal penalties, incurrence of investigatory or remedial obligations, or the imposition of injunctive relief. Under these environmental laws and regulations, we could be held strictly liable for the removal or remediation of previously released materials or property contamination regardless of whether we were responsible for the release or if our operations were standard in the industry at the time they were performed. Federal law and some state laws also allow the government to place a lien on real property for costs incurred by the government to address contamination on the property.
 
Changes in environmental laws and regulations occur frequently, and any changes that result in more stringent or costly material handling, storage, transport, disposal or cleanup requirements could require us to make significant expenditures to maintain compliance and may otherwise have a material adverse effect on our results of operations, competitive position, or financial condition as well as those of the oil and gas industry in general. For instance, in response to studies suggesting that emissions of certain gases, commonly referred to as greenhouse gases and including carbon dioxide and methane, may be contributing to warming of the Earth’s atmosphere, President Obama has expressed support for, and it is anticipated that the current session of Congress will consider legislation to regulate emissions of greenhouse gases. In addition, more than one-third of the states, either individually or through multi-state regional initiatives, have already taken legal measures to reduce emission of these gases, primarily through the planned development of greenhouse gas emission inventories and/or regional greenhouse gas cap and trade programs. In 2007, the U.S. Supreme Court held in a case, Massachusetts, et al. v. EPA, that greenhouse gases fall within the federal Clean Air Act’s definition of “air pollutant,” which could result in the regulation of greenhouse gas emissions from stationary sources under certain Clean Air Act programs, even if Congress does not adopt new legislation specifically addressing emissions of greenhouse gases. More recently, in July 2008, EPA released an “Advance Notice of Proposed Rulemaking,” regarding possible future regulation of greenhouse gases under the Clean Air Act. New legislation or regulatory programs that restrict emissions of greenhouse gases in areas in which we conduct business could have an adverse affect on our operations and demand for the oil and gas we produce.
 
Unless we replace our oil and natural gas reserves, our reserves and production will decline, which would adversely affect our cash flows and results of operations.
 
Unless we conduct successful development, exploitation and exploration activities or acquire properties containing proved reserves, our proved reserves will decline as those reserves are produced. Producing oil and natural gas reservoirs generally are characterized by declining production rates that vary


S-25


Table of Contents

depending upon reservoir characteristics and other factors. Our future oil and natural gas reserves and production, and therefore our cash flow and income, are highly dependent on our success in efficiently developing and exploiting our current reserves and economically finding or acquiring additional recoverable reserves. We may not be able to develop, exploit, find or acquire additional reserves to replace our current and future production.
 
The loss of senior management or technical personnel could adversely affect us.
 
To a large extent, we depend on the services of our senior management and technical personnel. The loss of the services of our senior management or technical personnel, including James J. Volker, our Chairman, President and Chief Executive Officer; James T. Brown, our Senior Vice President; Rick A. Ross, our Vice President, Operations; Peter W. Hagist, our Vice President, Permian Operations; J. Douglas Lang, our Vice President, Reservoir Engineering/Acquisitions; David M. Seery, our Vice President of Land; Michael J. Stevens, our Vice President and Chief Financial Officer; or Mark R. Williams, our Vice President, Exploration and Development, could have a material adverse effect on our operations. We do not maintain, nor do we plan to obtain, any insurance against the loss of any of these individuals.
 
The unavailability or high cost of additional drilling rigs, equipment, supplies, personnel and oil field services could adversely affect our ability to execute our exploration and development plans on a timely basis or within our budget.
 
Shortages or the high cost of drilling rigs, equipment, supplies or personnel could delay or adversely affect our exploration and development operations, which could have a material adverse effect on our business, financial condition, results of operations or cash flows.
 
Competition in the oil and gas industry is intense, which may adversely affect our ability to compete.
 
We operate in a highly competitive environment for acquiring properties, marketing oil and gas and securing trained personnel. Many of our competitors possess and employ financial, technical and personnel resources substantially greater than ours, which can be particularly important in the areas in which we operate. Those companies may be able to pay more for productive oil and gas properties and exploratory prospects and to evaluate, bid for and purchase a greater number of properties and prospects than our financial or personnel resources permit. Our ability to acquire additional prospects and to find and develop reserves in the future will depend on our ability to evaluate and select suitable properties and to consummate transactions in a highly competitive environment. Also, there is substantial competition for available capital for investment in the oil and gas industry. We may not be able to compete successfully in the future in acquiring prospective reserves, developing reserves, marketing hydrocarbons, attracting and retaining quality personnel and raising additional capital.
 
Our use of oil and natural gas price hedging contracts involves credit risk and may limit future revenues from price increases and result in significant fluctuations in our net income.
 
We enter into hedging transactions of our oil and natural gas production to reduce our exposure to fluctuations in the price of oil and natural gas. Our hedging transactions to date have consisted of financially settled crude oil and natural gas forward sales contracts, primarily costless collars, placed with major financial institutions. As of December 31, 2008, we had contracts, which include our 24.2% share of the Whiting USA Trust I hedges, covering the sale in 2009 of between 489,190 and 556,129 barrels of oil per month and between 44,874 and 52,353 MMBtu of natural gas per month. All our oil hedges expire in November 2013, and all our natural gas hedges expire in December 2012. See “Prospectus Supplement Summary — Recent Developments — Hedging Program” for pricing and a more detailed discussion of our hedging transactions.
 
We may in the future enter into these and other types of hedging arrangements to reduce our exposure to fluctuations in the market prices of oil and natural gas. Hedging transactions expose us to risk of financial loss in some circumstances, including if production is less than expected, the other party to the contract defaults on its obligations or there is a change in the expected differential between the underlying


S-26


Table of Contents

price in the hedging agreement and actual prices received. Hedging transactions may limit the benefit we may otherwise receive from increases in the price for oil and natural gas. Furthermore, if we do not engage in hedging transactions, then we may be more adversely affected by declines in oil and natural gas prices than our competitors who engage in hedging transactions. Additionally, hedging transactions may expose us to cash margin requirements.
 
Risks Relating to Our Common Stock
 
Our stock price may be volatile.
 
The market price of our common stock could be subject to significant fluctuations, and may decline. The following factors could affect our stock price:
 
  •      our operating and financial performance and prospects;
 
  •      quarterly variations in the rate of growth of our financial indicators, such as net income per share, net income and revenues;
 
  •      changes in revenue or earnings estimates or publication of research reports by analysts;
 
  •      speculation in the press or investment community;
 
  •      general market conditions, including fluctuations in commodity prices; and
 
  •      domestic and international economic, legal and regulatory factors unrelated to our performance.
 
The stock markets in general have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. These broad market fluctuations may adversely affect the trading price of our common stock.
 
We have no plans to pay dividends on our common stock. You may not receive funds without selling your shares.
 
We do not anticipate paying any cash dividends on our common stock in the foreseeable future. We currently intend to retain future earnings, if any, to finance the expansion of our business. Our future dividend policy is within the discretion of our board of directors and will depend upon various factors, including our business, financial condition, results of operations, capital requirements and investment opportunities. In addition, the agreements governing our indebtedness prohibit us from paying dividends.
 
Provisions in our organizational documents, our rights agreement and Delaware law could delay or prevent a change in control of our company, which could adversely affect the price of our common stock.
 
The existence of our rights agreement and some provisions in our organizational documents and under Delaware law could delay or prevent a change in control of our company, which could adversely affect the price of our common stock. The provisions in our certificate of incorporation and by-laws that could delay or prevent an unsolicited change in control of our company include a staggered board of directors, board authority to issue preferred stock, advance notice provisions for director nominations or business to be considered at a stockholder meeting and supermajority voting requirements. Our rights agreement provides each share of common stock, including shares offered through this prospectus supplement, the right to purchase one-hundredth of a share of our Series A Junior Participating Preferred Stock, which is exercisable only if a person or group has acquired, or announced an intention to acquire, 15% or more of our outstanding common stock. The rights have certain anti-takeover effects, in that they could have the effect of delaying or preventing a change in control of our company by causing substantial dilution to a person or group that attempts to acquire a significant interest in our company on terms not approved by our board of directors. In addition, Delaware law imposes some restrictions on mergers and other business combinations between us and any holder of 15% or more of our outstanding common stock. See “Description of Capital Stock — Preferred Stock,” “Description of Capital Stock — Preferred Share Purchase Right” and “Description of Capital Stock — Delaware Anti-Takeover Law and Charter and By-law Provisions” in the accompanying prospectus.


S-27


Table of Contents

 
USE OF PROCEEDS
 
We estimate that we will receive net proceeds of approximately $260.2 million from our sale of 8,000,000 shares of our common stock in this offering at an assumed public offering price of $33.94 per share (which was the last reported sale price on January 23, 2009), after deducting the underwriting discount and commissions and estimated offering expenses payable by us. If the underwriters’ exercise their over-allotment option in full, we estimate that we will receive net proceeds of approximately $299.3 million, after deducting the underwriting discount and commissions and estimated offering expenses payable by us. A $1.00 increase or decrease in the public offering price per share (assuming no change in the number of shares offered) would result in a corresponding increase or decrease in net proceeds of $7.7 million. Separately, a 10% increase or decrease in the number of shares of our common stock sold in this offering, assuming a public offering price of $33.94, would result in a corresponding increase or decrease in net proceeds of $26.1 million.
 
After using the net proceeds from this offering to temporarily reduce amounts outstanding under our credit facility, we expect to use a portion of the proceeds from this offering to increase our 2009 base capital budget by approximately $123.6 million to develop incremental opportunities we have identified in the Northern and Central Rockies. However, we may allocate this portion of the proceeds as well as the balance of the proceeds from this offering to either further develop these incremental projects or to expand the projects in our 2009 base capital budget that indicate the highest return based on drilling results through the time of such allocation. See “Prospectus Supplement Summary — Prospects to be Drilled in 2009 with Offering Proceeds” and “Prospectus Supplement Summary — 2009 Capital Budget and Major Development Areas.” Affiliates of some of the underwriters are lenders under our credit facility and, accordingly, will receive a substantial portion of the proceeds from this offering from our reduction of such facility. See “Underwriting — Other Relationships.” Borrowings under our credit agreement were incurred to fund capital expenditures for development and exploration and to acquire properties in the Flat Rock field in Uintah County, Utah, currently bear interest at the rate of 1.84% and mature in August 2010.


S-28


Table of Contents

 
CAPITALIZATION
 
The following table sets forth our capitalization as of September 30, 2008 on an actual basis and as adjusted giving effect to the sale of 8,000,000 shares of our common stock in this offering at an assumed public offering price of $33.94 per share (which was the last reported sale price on January 23, 2009), after deducting the underwriting discount and estimated offering expenses and the application of the estimated net proceeds of this offering as described under “Use of Proceeds”.
 
You should read this table in conjunction with our historical financial statements and related notes incorporated by reference in this prospectus supplement and the accompanying prospectus. The information below assumes the underwriters do not exercise their over-allotment option.
 
                 
    September 30, 2008  
          As Adjusted for
 
    Actual     this Offering(1)(2)  
    (In thousands)  
 
Cash and cash equivalents
  $ 20,644     $ 20,644  
                 
Long-term debt
               
Credit agreement
  $ 500,000     $ 239,841  
Senior subordinated notes
    618,560       618,560  
                 
Total long-term debt
    1,118,560       858,401  
Stockholders’ equity:
               
Common stock, $0.001 par value; 75,000,000 shares authorized, 42,584,833 shares issued and outstanding
    43       51  
Additional paid-in capital
    972,050       1,232,201  
Accumulated other comprehensive loss
    (15,867 )     (15,867 )
Retained earnings
    823,203       823,203  
                 
Total stockholders’ equity
    1,779,429       2,039,588  
                 
Total capitalization
  $ 2,897,989     $ 2,897,989  
                 
 
 
(1) Assumes that the underwriters will not exercise their option to purchase additional shares. If the underwriters exercise their option in full, then we will issue and sell an additional 1,200,000 shares of our common stock in this offering, and we will use the additional net proceeds of $39.1 million, after deducting the underwriting discount, initially to repay a portion of the debt outstanding under Whiting Oil and Gas Corporation’s credit agreement.
 
(2) A $1.00 increase or decrease in the public offering price per share (assuming no change in the number of shares offered) would result in a corresponding increase or decrease in total stockholders’ equity as of September 30, 2008 of $7.7 million. Separately, a 10% increase or decrease in the number of shares of common stock sold in this offering, assuming a public offering price of $33.94 per share (the last reported sale price of our common stock on January 23, 2009), would result in a corresponding increase or decrease in total stockholders’ equity as of September 30, 2008 of $26.1 million.


S-29


Table of Contents

 
PRICE RANGE OF COMMON STOCK AND DIVIDENDS
 
Our common stock is traded on the New York Stock Exchange under symbol “WLL”. The following table shows the high and low sale prices for our common stock for the periods presented.
 
                 
    High     Low  
 
2009
               
First Quarter (Through January 23, 2009)
  $ 44.99     $ 28.72  
2008
               
Fourth Quarter (Ended December 31, 2008)
  $ 69.58     $ 24.36  
Third Quarter (Ended September 30, 2008)
  $ 112.42     $ 62.09  
Second Quarter (Ended June 30, 2008)
  $ 108.53     $ 63.07  
First Quarter (Ended March 31, 2008)
  $ 66.19     $ 44.60  
2007
               
Fourth Quarter (Ended December 31, 2007)
  $ 59.06     $ 44.09  
Third Quarter (Ended September 30, 2007)
  $ 45.14     $ 35.85  
Second Quarter (Ended June 30, 2007)
  $ 47.50     $ 38.71  
First Quarter (Ended March 31, 2007)
  $ 46.04     $ 35.81  
 
On January 23, 2009, the last sale price of our common stock as reported on the New York Stock Exchange was $33.94 per share.
 
As of December 31, 2008, there were 890 stockholders of record and, as of January 18, 2009, approximately 31,849 beneficial owners of our common stock.
 
We have not paid any dividends since we were incorporated in July 2003. We do not anticipate paying any cash dividends on our common stock in the foreseeable future. We currently intend to retain future earnings, if any, to finance the expansion of our business. Our future dividend policy is within the discretion of our board of directors and will depend upon various factors, including our results of operations, financial condition, capital requirements and investment opportunities. In addition, the agreements governing our indebtedness prohibit us from paying dividends.


S-30


Table of Contents

 
UNDERWRITING
 
We intend to offer the shares through the underwriters. Merrill Lynch, Pierce, Fenner & Smith Incorporated is acting as the representative of the underwriters named below. Subject to the terms and conditions described in a purchase agreement among us and the underwriters, we have agreed to sell to the underwriters, and the underwriters severally have agreed to purchase from us, the number of shares listed opposite their names below.
 
         
Underwriter
 
Number of Shares
 
 
Merrill Lynch, Pierce, Fenner & Smith
 Incorporated
             
J.P. Morgan Securities Inc. 
       
Raymond James & Associates, Inc. 
       
Barclays Capital Inc. 
       
KeyBanc Capital Markets Inc. 
       
Wachovia Capital Markets, LLC
       
Jefferies & Company, Inc. 
       
RBC Capital Markets Corporation
       
Tristone Capital Co. 
       
         
 Total
       
         
 
The underwriters have agreed to purchase all of the shares sold under the purchase agreement if any of these shares are purchased. If an underwriter defaults, the purchase agreement provides that the purchase commitments of the nondefaulting underwriters may be increased or the purchase agreement may be terminated.
 
We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, or to contribute to payments the underwriters may be required to make in respect of those liabilities.
 
The underwriters are offering the shares, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel, including the validity of the shares, and other conditions contained in the purchase agreement, such as the receipt by the underwriters of officers’ certificates and legal opinions. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or part.
 
Commissions and Discounts
 
The representatives have advised us that the underwriters propose initially to offer the shares to the public at the public offering price on the cover page of this prospectus supplement and to dealers at that price less a concession not in excess of $      per share. The underwriters may allow, and the dealers may reallow, a discount not in excess of $      per share to other dealers. After the initial public offering, the public offering price, concession and discount may be changed.
 
The following table shows the public offering price, underwriting discount and proceeds to us before expenses. The information assumes either no exercise or full exercise by the underwriters of the overallotment option.
 
                         
    Per Share     Without Option     With Option  
 
Public offering price
  $       $       $    
Underwriting discount
  $       $       $    
Proceeds, before expenses, to us
  $       $       $  
 
The expenses of the offering, not including the underwriting discount, are estimated at $500,000 and are payable by us.


S-31


Table of Contents

Overallotment Option
 
We have granted an option to the underwriters to purchase up to 1,200,000 additional shares at the public offering price less the underwriting discount. The underwriters may exercise this option for 30 days from the date of this prospectus supplement solely to cover any overallotments. If the underwriters exercise this option, each will be obligated, subject to conditions contained in the purchase agreement, to purchase a number of additional shares proportionate to that underwriter’s initial amount reflected in the above table.
 
No Sale of Similar Securities
 
We, our executive officers and our directors have agreed, with exceptions, not to sell or transfer any of our common stock for 90 days after the date of this prospectus supplement without first obtaining the written consent of Merrill Lynch on behalf of the underwriters. Specifically, we have agreed not to directly or indirectly:
 
  •      offer, pledge, sell, or contract to sell any common stock;
 
  •      sell any option or contract to purchase any common stock;
 
  •      purchase any option or contract to sell any common stock;
 
  •      grant any option, right or warrant for the sale of any common stock;
 
  •      file a registration statement other than with respect to shares of our common stock or other securities, in each case, to be issued by us;
 
  •      lend or otherwise dispose of or transfer any common stock; or
 
  •      enter into any swap or other agreement that transfer, in whole or in part, the economic consequence of ownership of any common stock whether any such swap or transactions is to be settled by delivery of shares or other securities, in cash or otherwise.
 
This lock-up provision applies to common stock and to securities convertible into or exchangeable or exercisable for or repayable with common stock. It also applies to common stock owned now or acquired later by the person executing the agreement or for which the person executing the agreement later acquires power of disposition. The 90-day restricted period will be automatically extended if (1) during the last 17 days of the 90-day restricted period we issue an earnings release or material news or a material event relating to us occurs or (2) prior to the expiration of the 90-day restricted period, we announce that we will release earnings results or become aware that material news or a material event will occur during the 16-day period beginning on the last day of the 90-day restricted period, in which case the restrictions described above will continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. In addition, the lock-up provision will not restrict broker-dealers from engaging in market making and similar activities conducted in the ordinary course of their business.
 
New York Stock Exchange Listing
 
The shares are listed on the New York Stock Exchange under the symbol “WLL.”
 
Price Stabilization, Short Positions and Penalty Bids
 
Until the distribution of the shares is completed, SEC rules may limit underwriters and selling group members from bidding for and purchasing our common stock. However, the representative may engage in transactions that stabilize the price of the common stock, such as bids or purchases to peg, fix or maintain that price.
 
If the underwriters create a short position in the common stock in connection with the offering, i.e., if they sell more shares than are listed on the cover of this prospectus supplement, the representative may reduce that short position by purchasing shares in the open market. The representative may also elect to reduce any short position by exercising all or part of the overallotment option described above. Purchases of our common


S-32


Table of Contents

stock to stabilize its price or to reduce a short position may cause the price of our common stock to be higher than it might be in the absence of such purchases.
 
Neither we nor any of the underwriters makes any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of the common stock. In addition, neither we nor any of the underwriters makes any representation that the representative will engage in these transactions or that these transactions, once commenced, will not be discontinued without notice.
 
Electronic Distribution
 
In connection with the offering, certain of the underwriters or securities dealers may distribute prospectuses by electronic means, such as e-mail. Merrill Lynch will be facilitating Internet distribution for this offering to certain of its Internet subscription customers. Merrill Lynch intends to allocate a limited number of shares for sale to its online brokerage customers. An electronic prospectus supplement is available on the Internet Website maintained by Merrill Lynch. Other than the prospectus supplement in electronic format, the information on the Merrill Lynch Website is not part of this prospectus supplement.
 
Other Relationships
 
Some of the underwriters and their affiliates have engaged in, and may in the future engage in, investment banking and other commercial dealings in the ordinary course of business with us. In addition, affiliates of Merrill Lynch, Pierce, Fenner & Smith Incorporated, J.P. Morgan Securities Inc., KeyBanc Capital Markets Inc. and Wachovia Capital Markets, LLC (including Wachovia Bank, National Association and Wells Fargo Bank, N.A.) are lenders under Whiting Oil and Gas Corporation’s bank credit facility and each will receive its proportionate share of the net proceeds of the offering used to repay a portion of the outstanding balance under the credit facility. Because more than ten percent of the net proceeds may be paid to affiliates of members of the Financial Industry Regulatory Authority, Inc. participating in the offering, the offering will be conducted in accordance with FINRA Rule 5110(h). Because a bona fide independent market exists for our common stock, the FINRA does not require that we use a qualified independent underwriter.


S-33


Table of Contents

 
WHERE YOU CAN FIND MORE INFORMATION
 
We file annual, quarterly and current reports, proxy statements and other information with the SEC. We also filed a registration statement on Form S-3, including exhibits, under the Securities Act of 1933 with respect to the common stock offered by this prospectus supplement. This prospectus supplement is a part of the registration statement, but does not contain all of the information included in the registration statement or the exhibits. You may read and copy the registration statement and any other document that we file at the SEC’s public reference room at 100 F Street, N.E., Washington D.C. 20549. You can call the SEC at 1-800-SEC-0330 for further information on the operation of the public reference room. You can also find our public filings with the SEC on the internet at a web site maintained by the SEC located at http://www.sec.gov.
 
We are “incorporating by reference” specified documents that we file with the SEC, which means:
 
  •      incorporated documents are considered part of this prospectus supplement;
 
  •      we are disclosing important information to you by referring you to those documents; and
 
  •      information we file with the SEC will automatically update and supersede information contained in this prospectus supplement.
 
We incorporate by reference the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 after the date of this prospectus supplement and before the end of the offering of the securities pursuant to this prospectus supplement:
 
  •      our Annual Report on Form 10-K for the year ended December 31, 2007;
 
  •      our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2008, June 30, 2008 and September 30, 2008;
 
  •      our Current Reports on Form 8-K, dated January 14, 2008, February 21, 2008, May 4, 2008 (other than Item 7.01), May 30, 2008 (other than Item 7.01), December 23, 2008 and January 13, 2009;
 
  •      the description of our common stock contained in our Registration Statement on Form 8-A, dated November 14, 2003, and any amendment or report updating that description; and
 
  •      the description of our preferred share purchase rights contained in our Registration Statement on Form 8-A, dated February 24, 2006 and any amendment or report updating that description.
 
Information in this prospectus supplement supersedes related information in the documents listed above, and information in subsequently filed documents supersedes related information in this prospectus supplement, the accompanying prospectus and the incorporated documents.
 
You may request a copy of any of these filings, at no cost, by request directed to us at the following address or telephone number:
 
Whiting Petroleum Corporation
1700 Broadway, Suite 2300
Denver, Colorado 80290
(303) 837-1661
Attention: Corporate Secretary
 
You can also find these filings on our website at www.whiting.com. However, we are not incorporating the information on our website other than these filings into this prospectus.


S-34


Table of Contents

 
LEGAL MATTERS
 
Certain legal matters relating to this offering will be passed upon for us by the law firm of Foley & Lardner LLP. Certain legal matters relating to this offering will be passed upon for the underwriters by the law firm of Vinson & Elkins L.L.P.
 
EXPERTS
 
The financial statements and the related financial statement schedule, incorporated in this prospectus supplement and the accompanying prospectus by reference from Whiting Petroleum Corporation’s Annual Report on Form 10-K for the year ended December 31, 2007, and the effectiveness of Whiting Petroleum Corporation’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such financial statements and financial statement schedule have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.
 
Certain information with respect to our oil and natural gas reserves derived from the report of Cawley Gillespie & Associates, Inc., an independent petroleum engineering consultant, has been included in this prospectus supplement, and incorporated in this prospectus supplement and the accompanying prospectus by reference from Whiting Petroleum Corporation’s Annual Report on Form 10-K for the year-ended December 31, 2007, on the authority of said firm as an expert in petroleum engineering.


S-35


Table of Contents

PROSPECTUS
 
(WHITING LOGO)
 
 
Whiting Petroleum Corporation
 
Debt Securities
Common Stock
Preferred Stock
Warrants
Stock Purchase Contracts
Stock Purchase Units
 
 
 
 
We may offer and sell from time to time our securities in one or more classes or series and in amounts, at prices and on terms that we will determine at the times of the offerings. Our subsidiaries may guarantee any debt securities that we issue under this prospectus. In addition, selling stockholders to be named in a prospectus supplement may offer and sell from time to time shares of our common stock in such amounts as set forth in a prospectus supplement. Unless otherwise set forth in a prospectus supplement, we will not receive any proceeds from the sale of shares of our common stock by any selling stockholders.
 
We will provide specific terms of the securities, including the offering prices, in one or more supplements to this prospectus. The supplements may also add, update or change information contained in this prospectus. You should read this prospectus and the prospectus supplement relating to the specific issue of securities carefully before you invest.
 
We may offer the securities independently or together in any combination for sale directly to purchasers or through underwriters, dealers or agents to be designated at a future date. The supplements to this prospectus will provide the specific terms of the plan of distribution.
 
Our common stock is listed on the New York Stock Exchange under the symbol “WLL.”
 
Investment in our securities involves risks. See “Risk Factors” in our Annual Report on Form 10-K and in any applicable prospectus supplement and/or other offering material for a discussion of certain factors which should be considered in an investment of the securities which may be offered hereby.
 
 
 
 
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.
 
 
 
 
 
The date of this prospectus is May 8, 2006.


 

TABLE OF CONTENTS
 
         
    Page
 
    2  
    3  
    3  
    3  
    4  
    4  
    4  
    18  
    21  
    22  
    22  
    23  
    25  
    25  
 
ABOUT THIS PROSPECTUS
 
In this prospectus, “we,” “us,” “our” or “ours” refer to Whiting Petroleum Corporation.
 
This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf process, we may, from time to time, sell the securities or combinations of the securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities that we may offer and the shares of our common stock that selling stockholders may offer. Each time we offer securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under the heading “Where You Can Find More Information.”
 
You should rely only on the information contained or incorporated by reference in this prospectus and in any prospectus supplement. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making offers to sell or solicitations to buy the securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation. You should not assume that the information in this prospectus or any prospectus supplement, as well as the information we previously filed with the SEC that we incorporate by reference in this prospectus or any prospectus supplement, is accurate as of any date other than its respective date. Our business, financial condition, results of operations and prospects may have changed since those dates.


2


Table of Contents

 
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
 
This prospectus, any supplement to this prospectus and/or other offering material and the information incorporated by reference in this prospectus or any prospectus supplement and/or other offering material may contain forward-looking statements within the meaning of Private Securities Litigation Reform Act of 1995. We intend these forward-looking statements to be covered by the safe harbor provisions for forward-looking statements in the Private Securities Litigation Reform Act of 1995. Forward-looking statements include information concerning possible or assumed future risks and may be preceded by or include forward-looking words such as “believes,” “expects,” “may,” “anticipates,” “projects” or similar expressions. All statements other than statements of historical facts included in this prospectus or any supplement to this prospectus and/or other offering material, including those regarding our financial position, business strategy and plans and objectives of management for future operations, are forward-looking statements. We caution that these statements and any other forward-looking statements in this prospectus, any supplement to this prospectus and the information incorporated by reference in this prospectus or any prospectus supplement and/or other offering material only reflect our expectations and are not guarantees of performance. These statements involve risks, uncertainties and assumptions, including, among others, those we identify from time to time in materials that we file with the SEC that are incorporated by reference into this prospectus. Numerous important factors described in this prospectus, or any supplement to this prospectus and/or other offering material and the information incorporated by reference in this prospectus or any prospectus supplement and/or other offering material could affect these statements and could cause actual results to differ materially from our expectations. We undertake no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise.
 
WHITING PETROLEUM CORPORATION
 
We are an independent oil and natural gas holding company engaged in oil and natural gas exploitation, acquisition, exploration and production activities primarily in the Permian Basin, Rocky Mountains, Mid-Continent, Gulf Coast and Michigan regions of the United States. Since our inception in 1980, we have built a strong asset base and achieved steady growth through both property acquisitions and exploitation activities.
 
Our principal executive offices are located at 1700 Broadway, Suite 2300, Denver, Colorado 80290-2300, and our telephone number is (303) 837-1661.
 
SELLING STOCKHOLDERS
 
We may register shares of common stock covered by this prospectus for re-offers and resales by any selling stockholders to be named in a prospectus supplement. Because we are a well-known seasoned issuer, as defined in Rule 405 of the Securities Act of 1933, we may add secondary sales of shares of our common stock by any selling stockholders by filing a prospectus supplement with the SEC. We may register these shares to permit selling stockholders to resell their shares when they deem appropriate. A selling stockholder may resell all, a portion or none of their shares at any time and from time to time. Selling stockholders may also sell, transfer or otherwise dispose of some or all of their shares of our common stock in transactions exempt from the registration requirements of the Securities Act. We do not know when or in what amounts the selling stockholders may offer shares for sale under this prospectus and any prospectus supplement. We may pay all expenses incurred with respect to the registration of the shares of common stock owned by the selling stockholders, other than underwriting fees, discounts or commissions, which will be borne by the selling stockholders. We will provide you with a prospectus supplement naming the selling stockholder, the amount of shares to be registered and sold and any other terms of the shares of common stock being sold by a selling stockholder.


3


Table of Contents

 
USE OF PROCEEDS
 
We intend to use the net proceeds from the sales of the securities as set forth in the applicable prospectus supplement and/or other offering material.
 
RATIO OF EARNINGS TO FIXED CHARGES
 
The following table presents our ratios of consolidated earnings to fixed charges for the periods presented.
 
                                                 
    Three Months Ended
                               
    March 31,
    Years Ended December 31,  
    2006     2005     2004     2003     2002    
2001
 
 
Ratio of earnings to fixed charges(1)
    4.13 x     5.64 x     8.01 x     4.85 x     2.08 x     6.10x  
 
 
(1) For purposes of calculating the ratios of consolidated earnings to fixed charges, earnings consist of income before income taxes and before income or loss from equity investees, plus fixed charges and amortization of capitalized interest and distributed income of equity investees, less capitalized interest. Fixed charges consist of interest expensed, interest capitalized, amortized premiums, discounts and capitalized expenses related to indebtedness and an estimate of interest within rental expense.
 
We did not have any preferred stock outstanding and we did not pay or accrue any preferred stock dividends during the periods presented above.
 
DESCRIPTION OF DEBT SECURITIES
 
This section describes the general terms and provisions of the debt securities that we may issue separately, upon exercise of a debt warrant, in connection with a stock purchase contract or as part of a stock purchase unit from time to time in the form of one or more series of debt securities. The applicable prospectus supplement and/or other offering material will describe the specific terms of the debt securities offered through that prospectus supplement and/or other offering material as well as any general terms described in this section that will not apply to those debt securities.
 
Any debt securities issued using this prospectus (“Debt Securities”) will be our direct unsecured general obligations. The Debt Securities will be either our senior debt securities (“Senior Debt Securities”) or our subordinated debt securities (“Subordinated Debt Securities”). The Subordinated Debt Securities will be issued under the Subordinated Indenture (the “Subordinated Indenture”), dated as of April 19, 2005, among us, certain of our subsidiaries and J.P. Morgan Trust Company, National Association, as trustee. The Senior Debt Securities will be issued under a “Senior Indenture” among us, certain of our subsidiaries, if such subsidiaries are guarantors of the Senior Debt Securities, and a U.S. banking institution named as trustee in a prospectus supplement and/or other offering material. Together, the Senior Indenture and the Subordinated Indenture are called “Indentures.”
 
We are a holding company, and we primarily conduct our operations through subsidiaries. Unless the Debt Securities are guaranteed by our subsidiaries as described below, the rights of our company and our creditors, including holders of the Debt Securities, to participate in the assets of any subsidiary upon the latter’s liquidation or reorganization, will be subject to the prior claims of the subsidiary’s creditors, except to the extent that we may ourself be a creditor with recognized claims against such subsidiary.
 
We have summarized selected provisions of the Indentures below. The summary is not complete. Each Indenture has been filed with the SEC as an exhibit to the registration statement of which this prospectus is a part, and you should read the Indentures for provisions that may be important to you. In the summary below we have included references to article or section numbers of the applicable Indenture so that you can easily locate these provisions. Whenever we refer in this prospectus or in the prospectus supplement and/or other offering material to particular article or sections or defined terms of the Indentures, those article or


4


Table of Contents

sections or defined terms are incorporated by reference herein or therein, as applicable. Capitalized terms used in the summary have the meanings specified in the Indentures.
 
General
 
The Indentures provide that Debt Securities in separate series may be issued thereunder from time to time without limitation as to aggregate principal amount. We may specify a maximum aggregate principal amount for the Debt Securities of any series (Section 301). We will determine the terms and conditions of the Debt Securities, including the maturity, principal and interest, but those terms must be consistent with the Indenture. We have the right to “reopen” a previous issue of a series of debt by issuing additional Debt Securities of such series.
 
The Senior Debt Securities will rank equally with all of our other senior unsecured and unsubordinated debt (“Senior Debt”). The Subordinated Debt Securities will be subordinated in right of payment to the prior payment in full of all of our Senior Debt (as defined) as described under “— Subordination of Subordinated Debt Securities” and in the prospectus supplement and/or other offering material applicable to any Subordinated Debt Securities.
 
If specified in the prospectus supplement and/or other offering material, certain of our domestic subsidiaries (the “Subsidiary Guarantors”) will fully and unconditionally guarantee (the “Subsidiary Guarantees”) on a joint and several basis the Debt Securities as described under “— Subsidiary Guarantees” and in the prospectus supplement and/or other offering material. The Subsidiary Guarantees will be unsecured obligations of each Subsidiary Guarantor. Subsidiary Guarantees of Subordinated Debt Securities will be subordinated to the Senior Debt of the Subsidiary Guarantors on the same basis as the Subordinated Debt Securities are subordinated to our Senior Debt (Article Thirteen).
 
The applicable prospectus supplement and/or other offering material will set forth the price or prices at which the Debt Securities to be offered will be issued and will describe the following terms of such Debt Securities:
 
(1) the title of the Debt Securities;
 
(2) whether the Debt Securities are Senior Debt Securities or Subordinated Debt Securities and, if Subordinated Debt Securities, the related subordination terms;
 
(3) whether any of the Subsidiary Guarantors will provide Subsidiary Guarantees of the Debt Securities;
 
(4) any limit on the aggregate principal amount of the Debt Securities;
 
(5) the dates on which the principal of the Debt Securities will be payable;
 
(6) the interest rate that the Debt Securities will bear and the interest payment dates for the Debt Securities;
 
(7) the places where payments on the Debt Securities will be payable;
 
(8) any terms upon which the Debt Securities may be redeemed, in whole or in part, at our option;
 
(9) any sinking fund or other provisions that would obligate us to repurchase or otherwise redeem the Debt Securities;
 
(10) the portion of the principal amount, if less than all, of the Debt Securities that will be payable upon declaration of acceleration of the Maturity of the Debt Securities;
 
(11) whether the Debt Securities are defeasible;
 
(12) any addition to or change in the Events of Default;


5


Table of Contents

(13) whether the Debt Securities are convertible into our common stock and, if so, the terms and conditions upon which conversion will be effected, including the initial conversion price or conversion rate and any adjustments thereto and the conversion period;
 
(14) if convertible into our common stock or any of our other securities, the terms on which such Debt Securities are convertible;
 
(15) any addition to or change in the covenants in the Indenture applicable to the Debt Securities; and
 
(16) any other terms of the Debt Securities not inconsistent with the provisions of the Indenture (Section 301).
 
The Indentures do not limit the amount of Debt Securities that may be issued. Each Indenture allows Debt Securities to be issued up to the principal amount that may be authorized by our company and may be in any currency or currency unit designated by us.
 
Debt Securities, including Original Issue Discount Securities, may be sold at a substantial discount below their principal amount. Special United States federal income tax considerations applicable to Debt Securities sold at an original issue discount may be described in the applicable prospectus supplement and/or other offering material. In addition, special United States federal income tax or other considerations applicable to any Debt Securities that are denominated in a currency or currency unit other than United States dollars may be described in the applicable prospectus supplement and/or other offering material.
 
Senior Debt Securities
 
The Senior Debt Securities will be unsecured senior obligations and will rank equally with all other senior unsecured and unsubordinated debt. The Senior Debt Securities will, however, be subordinated in right of payment to all our secured indebtedness to the extent of the value of the assets securing such indebtedness. Except as provided in the applicable Senior Indenture or specified in any authorizing resolution or supplemental indenture relating to a series of Senior Debt Securities to be issued, no Senior Indenture will limit the amount of additional indebtedness that may rank equally with the Senior Debt Securities or the amount of indebtedness, secured or otherwise, that may be incurred or preferred stock that may be issued by any of our subsidiaries.
 
Subordination of Subordinated Debt Securities
 
The indebtedness evidenced by the Subordinated Debt Securities will, to the extent set forth in the Subordinated Indenture with respect to each series of Subordinated Debt Securities, be subordinate in right of payment to the prior payment in full of all of our Senior Debt, including the Senior Debt Securities, and it may also be senior in right of payment to all of our Subordinated Debt (Article Twelve of the Subordinated Indenture). The prospectus supplement and/or other offering material relating to any Subordinated Debt Securities will summarize the subordination provisions of the Subordinated Indenture applicable to that series including:
 
  •      the applicability and effect of such provisions upon any payment or distribution respecting that series following any liquidation, dissolution or other winding-up, or any assignment for the benefit of creditors or other marshaling of assets or any bankruptcy, insolvency or similar proceedings;
 
  •      the applicability and effect of such provisions in the event of specified defaults with respect to any Senior Debt, including the circumstances under which and the periods in which we will be prohibited from making payments on the Subordinated Debt Securities; and
 
  •      the definition of Senior Debt applicable to the Subordinated Debt Securities of that series and, if the series is issued on a senior subordinated basis, the definition of Subordinated Debt applicable to that series.


6


Table of Contents

 
The prospectus supplement and/or other offering material will also describe as of a recent date the approximate amount of Senior Debt to which the Subordinated Debt Securities of that series will be subordinated.
 
The failure to make any payment on any of the Subordinated Debt Securities by reason of the subordination provisions of the Subordinated Indenture described in the prospectus supplement and/or other offering material will not be construed as preventing the occurrence of an Event of Default with respect to the Subordinated Debt Securities arising from any such failure to make payment.
 
The subordination provisions described above will not be applicable to payments in respect of the Subordinated Debt Securities from a defeasance trust established in connection with any legal defeasance or covenant defeasance of the Subordinated Debt Securities as described under “— Legal Defeasance and Covenant Defeasance.”
 
Subsidiary Guarantees
 
If specified in the prospectus supplement and/or other offering material, the Subsidiary Guarantors will guarantee the Debt Securities of a series. Unless otherwise indicated in the prospectus supplement and/or other offering material, the following provisions will apply to the Subsidiary Guarantees of the Subsidiary Guarantors.
 
Subject to the limitations described below and in the prospectus supplement and/or other offering material, the Subsidiary Guarantors will, jointly and severally, fully and unconditionally guarantee the prompt payment when due, whether at Stated Maturity, by acceleration or otherwise, of all our payment obligations under the Indentures and the Debt Securities of a series, whether for principal of, premium, if any, or interest on the Debt Securities or otherwise (all such obligations guaranteed by a Subsidiary Guarantor being herein called the “Guaranteed Obligations”). The Subsidiary Guarantors will also pay all expenses (including reasonable counsel fees and expenses) incurred by the applicable Trustee in enforcing any rights under a Subsidiary Guarantee with respect to a Subsidiary Guarantor (Section 1302).
 
In the case of Subordinated Debt Securities, a Subsidiary Guarantor’s Subsidiary Guarantee will be subordinated in right of payment to the Senior Debt of such Subsidiary Guarantor on the same basis as the Subordinated Debt Securities are subordinated to our Senior Debt. No payment will be made by any Subsidiary Guarantor under its Subsidiary Guarantee during any period in which payments by us on the Subordinated Debt Securities are suspended by the subordination provisions of the Subordinated Indenture (Article Fourteen of the Subordinated Indenture).
 
Each Subsidiary Guarantee will be limited in amount to an amount not to exceed the maximum amount that can be guaranteed by the relevant Subsidiary Guarantor without rendering such Subsidiary Guarantee voidable under applicable law relating to fraudulent conveyance or fraudulent transfer or similar laws affecting the rights of creditors generally (Section 1306).
 
Each Subsidiary Guarantee will be a continuing guarantee and will:
 
(1) remain in full force and effect until either (a) payment in full of all the applicable Debt Securities (or such Debt Securities are otherwise satisfied and discharged in accordance with the provisions of the applicable Indenture) or (b) released as described in the following paragraph;
 
(2) be binding upon each Subsidiary Guarantor; and
 
(3) inure to the benefit of and be enforceable by the applicable Trustee, the Holders and their successors, transferees and assigns.
 
In the event that a Subsidiary Guarantor ceases to be a Subsidiary, either legal defeasance or covenant defeasance occurs with respect to the series or all or substantially all of the assets or all of the Capital Stock of such Subsidiary Guarantor is sold, including by way of sale, merger, consolidation or otherwise, such Subsidiary Guarantor will be released and discharged of its obligations under its Subsidiary Guarantee without any further action required on the part of the Trustee or any Holder, and no other person acquiring or owning


7


Table of Contents

the assets or Capital Stock of such Subsidiary Guarantor will be required to enter into a Subsidiary Guarantee (Section 1304). In addition, the prospectus supplement and/or other offering material may specify additional circumstances under which a Subsidiary Guarantor can be released from its Subsidiary Guarantee.
 
Conversion Rights
 
The Debt Securities may be converted into other securities of our company, if at all, according to the terms and conditions of an applicable prospectus supplement and/or other offering material. Such terms will include the conversion price, the conversion period, provisions as to whether conversion will be at the option of the holders of such series of Debt Securities or at the option of our company, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption of such series of Debt Securities.
 
Form, Exchange and Transfer
 
The Debt Securities of each series will be issuable only in fully registered form, without coupons, and, unless otherwise specified in the applicable prospectus supplement and/or other offering material, only in denominations of $1,000 and integral multiples thereof (Section 302).
 
At the option of the Holder, subject to the terms of the applicable Indenture and the limitations applicable to Global Securities, Debt Securities of each series will be exchangeable for other Debt Securities of the same series of any authorized denomination and of a like tenor and aggregate principal amount (Section 305).
 
Subject to the terms of the applicable Indenture and the limitations applicable to Global Securities, Debt Securities may be presented for exchange as provided above or for registration of transfer (duly endorsed or with the form of transfer endorsed thereon duly executed) at the office of the Security Registrar or at the office of any transfer agent designated by us for such purpose. No service charge will be made for any registration of transfer or exchange of Debt Securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in that connection. Such transfer or exchange will be effected upon the Security Registrar or such transfer agent, as the case may be, being satisfied with the documents of title and identity of the person making the request. The Security Registrar and any other transfer agent initially designated by us for any Debt Securities will be named in the applicable prospectus supplement and/or other offering material (Section 305). We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each Place of Payment for the Debt Securities of each series (Section 1002).
 
If the Debt Securities of any series (or of any series and specified tenor) are to be redeemed in part, we will not be required to (1) issue, register the transfer of or exchange any Debt Security of that series (or of that series and specified tenor, as the case may be) during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any such Debt Security that may be selected for redemption and ending at the close of business on the day of such mailing or (2) register the transfer of or exchange any Debt Security so selected for redemption, in whole or in part, except the unredeemed portion of any such Debt Security being redeemed in part (Section 305).
 
Payment and Paying Agents
 
Unless otherwise indicated in the applicable prospectus supplement and/or other offering material, payment of interest on a Debt Security on any Interest Payment Date will be made to the Person in whose name such Debt Security (or one or more Predecessor Debt Securities) is registered at the close of business on the Regular Record Date for such interest (Section 307).
 
Unless otherwise indicated in the applicable prospectus supplement and/or other offering material, principal of and any premium and interest on the Debt Securities of a particular series will be payable at the office of such Paying Agent or Paying Agents as we may designate for such purpose from time to time, except


8


Table of Contents

that at our option payment of any interest on Debt Securities in certificated form may be made by check mailed to the address of the Person entitled thereto as such address appears in the Security Register. Unless otherwise indicated in the applicable prospectus supplement and/or other offering material, the corporate trust office of the Trustee under the Senior Indenture in The City of New York will be designated as sole Paying Agent for payments with respect to Senior Debt Securities of each series, and the corporate trust office of the Trustee under the Subordinated Indenture in The City of New York will be designated as the sole Paying Agent for payment with respect to Subordinated Debt Securities of each series. Any other Paying Agents initially designated by us for the Debt Securities of a particular series will be named in the applicable prospectus supplement and/or other offering material. We may at any time designate additional Paying Agents or rescind the designation of any Paying Agent or approve a change in the office through which any Paying Agent acts, except that we will be required to maintain a Paying Agent in each Place of Payment for the Debt Securities of a particular series (Section 1002).
 
All money paid by us to a Paying Agent for the payment of the principal of or any premium or interest on any Debt Security which remain unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the Holder of such Debt Security thereafter may look only to us for payment (Section 1003).
 
Consolidation, Merger and Sale of Assets
 
We may not consolidate with or merge into, or transfer, lease or otherwise dispose of all or substantially all of our assets to, any Person (a “successor Person”), and may not permit any Person to consolidate with or merge into us, unless:
 
(1) the successor Person (if any) is a corporation, partnership, trust or other entity organized and validly existing under the laws of any domestic jurisdiction and assumes our obligations on the Debt Securities and under the Indentures;
 
(2) immediately before and after giving pro forma effect to the transaction, no Event of Default, and no event which, after notice or lapse of time or both, would become an Event of Default, has occurred and is continuing; and
 
(3) several other conditions, including any additional conditions with respect to any particular Debt Securities specified in the applicable prospectus supplement and/or other offering material, are met (Section 801).
 
Events of Default
 
Unless otherwise specified in the prospectus supplement and/or other offering material, each of the following will constitute an Event of Default under the applicable Indenture with respect to Debt Securities of any series:
 
(1) failure to pay principal of or any premium on any Debt Security of that series when due, whether or not, in the case of Subordinated Debt Securities, such payment is prohibited by the subordination provisions of the Subordinated Indenture;
 
(2) failure to pay any interest on any Debt Securities of that series when due, continued for 30 days, whether or not, in the case of Subordinated Debt Securities, such payment is prohibited by the subordination provisions of the Subordinated Indenture;
 
(3) failure to deposit any sinking fund payment, when due, in respect of any Debt Security of that series, whether or not, in the case of Subordinated Debt Securities, such deposit is prohibited by the subordination provisions of the Subordinated Indenture;
 
(4) failure to perform or comply with the provisions described under “— Consolidation, Merger and Sale of Assets”;


9


Table of Contents

(5) failure to perform any of our other covenants in such Indenture (other than a covenant included in such Indenture solely for the benefit of a series other than that series), continued for 60 days after written notice has been given by the applicable Trustee, or the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series, as provided in such Indenture;
 
(6) Indebtedness of ourself, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor, is not paid within any applicable grace period after final maturity or is accelerated by its holders because of a default and the total amount of such Indebtedness unpaid or accelerated exceeds $20.0 million;
 
(7) any judgment or decree for the payment of money in excess of $20.0 million is entered against us, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor, remains outstanding for a period of 60 consecutive days following entry of such judgment and is not discharged, waived or stayed;
 
(8) certain events of bankruptcy, insolvency or reorganization affecting us, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor; and
 
(9) if any Subsidiary Guarantor has guaranteed such series, the Subsidiary Guarantee of any such Subsidiary Guarantor is held by a final non-appealable order or judgment of a court of competent jurisdiction to be unenforceable or invalid or ceases for any reason to be in full force and effect (other than in accordance with the terms of the applicable Indenture) or any Subsidiary Guarantor or any Person acting on behalf of any Subsidiary Guarantor denies or disaffirms such Subsidiary Guarantor’s obligations under its Subsidiary Guarantee (other than by reason of a release of such Subsidiary Guarantor from its Subsidiary Guarantee in accordance with the terms of the applicable Indenture) (Section 501).
 
If an Event of Default (other than an Event of Default with respect to Whiting Petroleum Corporation described in clause (8) above) with respect to the Debt Securities of any series at the time Outstanding occurs and is continuing, either the applicable Trustee or the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series by notice as provided in the Indenture may declare the principal amount of the Debt Securities of that series (or, in the case of any Debt Security that is an Original Issue Discount Debt Security, such portion of the principal amount of such Debt Security as may be specified in the terms of such Debt Security) to be due and payable immediately. If an Event of Default with respect to Whiting Petroleum Corporation described in clause (8) above with respect to the Debt Securities of any series at the time Outstanding occurs, the principal amount of all the Debt Securities of that series (or, in the case of any such Original Issue Discount Security, such specified amount) will automatically, and without any action by the applicable Trustee or any Holder, become immediately due and payable. After any such acceleration, but before a judgment or decree based on acceleration, the Holders of a majority in principal amount of the Outstanding Debt Securities of that series may, under certain circumstances, rescind and annul such acceleration if all Events of Default, other than the non-payment of accelerated principal (or other specified amount), have been cured or waived as provided in the applicable Indenture (Section 502). For information as to waiver of defaults, see “— Modification and Waiver” below.
 
Subject to the provisions of the Indentures relating to the duties of the Trustees in case an Event of Default has occurred and is continuing, each Trustee will be under no obligation to exercise any of its rights or powers under the applicable Indenture at the request or direction of any of the Holders, unless such Holders have offered to such Trustee reasonable indemnity (Section 603). Subject to such provisions for the indemnification of the Trustees, the Holders of a majority in principal amount of the Outstanding Debt Securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or exercising any trust or power conferred on the Trustee with respect to the Debt Securities of that series (Section 512).


10


Table of Contents

No Holder of a Debt Security of any series will have any right to institute any proceeding with respect to the applicable Indenture, or for the appointment of a receiver or a trustee, or for any other remedy thereunder, unless:
 
(1) such Holder has previously given to the Trustee under the applicable Indenture written notice of a continuing Event of Default with respect to the Debt Securities of that series;
 
(2) the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series have made written request, and such Holder or Holders have offered reasonable indemnity, to the Trustee to institute such proceeding as trustee; and
 
(3) the Trustee has failed to institute such proceeding, and has not received from the Holders of a majority in principal amount of the Outstanding Debt Securities of that series a direction inconsistent with such request, within 60 days after such notice, request and offer (Section 507).
 
However, such limitations do not apply to a suit instituted by a Holder of a Debt Security for the enforcement of payment of the principal of or any premium or interest on such Debt Security on or after the applicable due date specified in such Debt Security or, if applicable, to convert such Debt Security (Section 508).
 
We will be required to furnish to each Trustee annually a statement by certain of our officers as to whether or not we, to their knowledge, are in default in the performance or observance of any of the terms, provisions and conditions of the applicable Indenture and, if so, specifying all such known defaults (Section 1004).
 
Modification and Waiver
 
Modifications and amendments of an Indenture may be made by us, the Subsidiary Guarantors, if applicable, and the applicable Trustee with the consent of the Holders of a majority in principal amount of the Outstanding Debt Securities of each series affected by such modification or amendment; provided, however, that no such modification or amendment may, without the consent of the Holder of each Outstanding Debt Security affected thereby:
 
(1) change the Stated Maturity of the principal of, or any installment of principal of or interest on, any Debt Security;
 
(2) reduce the principal amount of, or any premium or interest on, any Debt Security;
 
(3) reduce the amount of principal of an Original Issue Discount Security or any other Debt Security payable upon acceleration of the Maturity thereof;
 
(4) change the place or currency of payment of principal of, or any premium or interest on, any Debt Security;
 
(5) impair the right to institute suit for the enforcement of any payment due on or any conversion right with respect to any Debt Security;
 
(6) modify the subordination provisions in the case of Subordinated Debt Securities, or modify any conversion provisions, in either case in a manner adverse to the Holders of the Subordinated Debt Securities;
 
(7) except as provided in the applicable Indenture, release the Subsidiary Guarantee of a Subsidiary Guarantor;
 
(8) reduce the percentage in principal amount of Outstanding Debt Securities of any series, the consent of whose Holders is required for modification or amendment of the Indenture;
 
(9) reduce the percentage in principal amount of Outstanding Debt Securities of any series necessary for waiver of compliance with certain provisions of the Indenture or for waiver of certain defaults; or


11


Table of Contents

(10) modify such provisions with respect to modification, amendment or waiver (Section 902).
 
The Holders of a majority in principal amount of the Outstanding Debt Securities of any series may waive compliance by us with certain restrictive provisions of the applicable Indenture (Section 1009). The Holders of a majority in principal amount of the Outstanding Debt Securities of any series may waive any past default under the applicable Indenture, except a default in the payment of principal, premium or interest and certain covenants and provisions of the Indenture which cannot be amended without the consent of the Holder of each Outstanding Debt Security of such series (Section 513).
 
Each of the Indentures provides that in determining whether the Holders of the requisite principal amount of the Outstanding Debt Securities have given or taken any direction, notice, consent, waiver or other action under such Indenture as of any date:
 
(1) the principal amount of an Original Issue Discount Security that will be deemed to be Outstanding will be the amount of the principal that would be due and payable as of such date upon acceleration of maturity to such date;
 
(2) if, as of such date, the principal amount payable at the Stated Maturity of a Debt Security is not determinable (for example, because it is based on an index), the principal amount of such Debt Security deemed to be Outstanding as of such date will be an amount determined in the manner prescribed for such Debt Security; and
 
(3) the principal amount of a Debt Security denominated in one or more foreign currencies or currency units that will be deemed to be Outstanding will be the United States-dollar equivalent, determined as of such date in the manner prescribed for such Debt Security, of the principal amount of such Debt Security (or, in the case of a Debt Security described in clause (1) or (2) above, of the amount described in such clause).
 
Certain Debt Securities, including those owned by us, any Subsidiary Guarantor or any of our other Affiliates, will not be deemed to be Outstanding (Section 101).
 
Except in certain limited circumstances, we will be entitled to set any day as a record date for the purpose of determining the Holders of Outstanding Debt Securities of any series entitled to give or take any direction, notice, consent, waiver or other action under the applicable Indenture, in the manner and subject to the limitations provided in the Indenture. In certain limited circumstances, the Trustee will be entitled to set a record date for action by Holders. If a record date is set for any action to be taken by Holders of a particular series, only persons who are Holders of Outstanding Debt Securities of that series on the record date may take such action. To be effective, such action must be taken by Holders of the requisite principal amount of such Debt Securities within a specified period following the record date. For any particular record date, this period will be 180 days or such other period as may be specified by us (or the Trustee, if it set the record date), and may be shortened or lengthened (but not beyond 180 days) from time to time (Section 104).
 
Satisfaction and Discharge
 
Each Indenture will be discharged and will cease to be of further effect as to all outstanding Debt Securities of any series issued thereunder, when:
 
(1) either:
 
(a) all outstanding Debt Securities of that series that have been authenticated (except lost, stolen or destroyed Debt Securities that have been replaced or paid and Debt Securities for whose payment money has theretofore been deposited in trust and thereafter repaid to us) have been delivered to the Trustee for cancellation; or
 
(b) all outstanding Debt Securities of that series that have not been delivered to the Trustee for cancellation have become due and payable or will become due and payable at their Stated Maturity within one year or are to be called for redemption within one year


12


Table of Contents

under arrangements satisfactory to the Trustee and in any case we have irrevocably deposited with the Trustee as trust funds money in an amount sufficient, without consideration of any reinvestment of interest, to pay the entire indebtedness of such Debt Securities not delivered to the Trustee for cancellation, for principal, premium, if any, and accrued interest to the Stated Maturity or redemption date;
 
(2) we have paid or caused to be paid all other sums payable by us under the Indenture with respect to the Debt Securities of that series; and
 
(3) we have delivered an Officers’ Certificate and an Opinion of Counsel to the Trustee stating that all conditions precedent to satisfaction and discharge of the Indenture with respect to the Debt Securities of that series have been satisfied (Article Four).
 
Legal Defeasance and Covenant Defeasance
 
If and to the extent indicated in the applicable prospectus supplement and/or other offering material, we may elect, at our option at any time, to have the provisions of Section 1502, relating to defeasance and discharge of indebtedness, which we call “legal defeasance” or Section 1503, relating to defeasance of certain restrictive covenants applied to the Debt Securities of any series, or to any specified part of a series, which we call “covenant defeasance” (Section 1501).
 
Legal Defeasance.  The Indentures provide that, upon our exercise of our option (if any) to have Section 1502 applied to any Debt Securities, we and, if applicable, each Subsidiary Guarantor will be discharged from all our obligations, and, if such Debt Securities are Subordinated Debt Securities, the provisions of the Subordinated Indenture relating to subordination will cease to be effective, with respect to such Debt Securities (except for certain obligations to convert, exchange or register the transfer of Debt Securities, to replace stolen, lost or mutilated Debt Securities, to maintain paying agencies and to hold moneys for payment in trust) upon the deposit in trust for the benefit of the Holders of such Debt Securities of money or United States Government Obligations, or both, which, through the payment of principal and interest in respect thereof in accordance with their terms, will provide money in an amount sufficient to pay the principal of and any premium and interest on such Debt Securities on the respective Stated Maturities in accordance with the terms of the applicable Indenture and such Debt Securities. Such defeasance or discharge may occur only if, among other things:
 
(1) we have delivered to the applicable Trustee an Opinion of Counsel to the effect that we have received from, or there has been published by, the United States Internal Revenue Service a ruling, or there has been a change in tax law, in either case to the effect that Holders of such Debt Securities will not recognize gain or loss for federal income tax purposes as a result of such deposit and legal defeasance and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit and legal defeasance were not to occur;
 
(2) no Event of Default or event that with the passing of time or the giving of notice, or both, shall constitute an Event of Default shall have occurred and be continuing at the time of such deposit or, with respect to any Event of Default described in clause (8) under “— Events of Default,” at any time until 121 days after such deposit;
 
(3) such deposit and legal defeasance will not result in a breach or violation of, or constitute a default under, any agreement or instrument to which we are a party or by which we are bound;
 
(4) in the case of Subordinated Debt Securities, at the time of such deposit, no default in the payment of all or a portion of principal of (or premium, if any) or interest on any of our Senior Debt shall have occurred and be continuing, no event of default shall have resulted in the acceleration of any of our Senior Debt and no other event of default with respect to any of our Senior Debt shall have occurred and be continuing permitting after notice or the lapse of time, or both, the acceleration thereof; and


13


Table of Contents

(5) we have delivered to the Trustee an Opinion of Counsel to the effect that such deposit shall not cause the Trustee or the trust so created to be subject to the Investment Company Act of 1940 (Sections 1502 and 1504).
 
Covenant Defeasance.  The Indentures provide that, upon our exercise of our option (if any) to have Section 1503 applied to any Debt Securities, we may omit to comply with certain restrictive covenants (but not to conversion, if applicable), including those that may be described in the applicable prospectus supplement and/or other offering material, the occurrence of certain Events of Default, which are described above in clause (5) (with respect to such restrictive covenants) and clauses (6), (7) and (9) under “Events of Default” and any that may be described in the applicable prospectus supplement and/or other offering material, will not be deemed to either be or result in an Event of Default and, if such Debt Securities are Subordinated Debt Securities, the provisions of the Subordinated Indenture relating to subordination will cease to be effective, in each case with respect to such Debt Securities. In order to exercise such option, we must deposit, in trust for the benefit of the Holders of such Debt Securities, money or United States Government Obligations, or both, which, through the payment of principal and interest in respect thereof in accordance with their terms, will provide money in an amount sufficient to pay the principal of and any premium and interest on such Debt Securities on the respective Stated Maturities in accordance with the terms of the applicable Indenture and such Debt Securities. Such covenant defeasance may occur only if we have delivered to the applicable Trustee an Opinion of Counsel that in effect says that Holders of such Debt Securities will not recognize gain or loss for federal income tax purposes as a result of such deposit and covenant defeasance and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit and covenant defeasance were not to occur, and the requirements set forth in clauses (2), (3), (4) and (5) above are satisfied. If we exercise this option with respect to any Debt Securities and such Debt Securities were declared due and payable because of the occurrence of any Event of Default, the amount of money and United States Government Obligations so deposited in trust would be sufficient to pay amounts due on such Debt Securities at the time of their respective Stated Maturities but may not be sufficient to pay amounts due on such Debt Securities upon any acceleration resulting from such Event of Default. In such case, we would remain liable for such payments (Sections 1503 and 1504).
 
If we exercise either our legal defeasance or covenant defeasance option, any Subsidiary Guarantees will terminate (Section 1304).
 
Notices
 
Notices to Holders of Debt Securities will be given by mail to the addresses of such Holders as they may appear in the Security Register (Sections 101 and 106).
 
Title
 
We, the Subsidiary Guarantors, the Trustees and any agent of us, the Subsidiary Guarantors or a Trustee may treat the Person in whose name a Debt Security is registered as the absolute owner of the Debt Security (whether or not such Debt Security may be overdue) for the purpose of making payment and for all other purposes (Section 308).
 
Governing Law
 
The Indentures and the Debt Securities will be governed by, and construed in accordance with, the law of the State of New York (Section 112).
 
Regarding the Trustee
 
We may from time to time maintain lines of credit, and have other customary banking relationships, with the trustee or its affiliates under the Senior Indenture or the trustee under the Subordinated Indenture.
 
The indentures and provisions of the Trust Indenture Act of 1939, which we refer to in this prospectus as the Trust Indenture Act, that are incorporated by reference therein, contain limitations on the rights of the


14


Table of Contents

trustee, should it become one of our creditors, to obtain payment of claims in certain cases or to realize on certain property received by it in respect of any such claim as security or otherwise. The trustee is permitted to engage in other transactions with us or any of our affiliates; provided, however, that if it acquires any conflicting interest (as defined under the Trust Indenture Act), it must eliminate such conflict or resign.
 
Book-Entry, Delivery and Form
 
Except as set forth below, Debt Securities will be represented by one or more permanent global notes in registered form without interest coupons (collectively, the “Global Notes”). The Global Notes will be deposited upon issuance with the trustee as custodian for The Depository Trust Company (“DTC”), in New York, New York, and registered in the name of DTC’s nominee, Cede & Co., in each case for credit to an account of a direct or indirect participant in DTC as described below. Beneficial interests in the Global Notes may be held through the Euroclear System (“Euroclear”) and Clearstream Banking, S.A. (“Clearstream”) (as indirect participants in DTC).
 
Except as set forth below, the Global Notes may be transferred, in whole but not in part, only to another nominee of DTC or to a successor of DTC or its nominee. Beneficial interests in the Global Notes may not be exchanged for definitive notes in registered, certificated form (“Certificated Notes”), except in the limited circumstances described below. See “— Exchange of Global Notes for Certificated Notes.” In addition, transfers of beneficial interests in the Global Notes will be subject to the applicable rules and procedures of DTC and its direct or indirect participants (including, if applicable, those of Euroclear and Clearstream), which may change from time to time.
 
Depository Procedures
 
The following description of the operations and procedures of DTC, Euroclear and Clearstream are provided solely as a matter of convenience. These operations and procedures are solely within the control of the respective settlement systems and are subject to changes by them. We take no responsibility for these operations and procedures and urge investors to contact the system or their participants directly to discuss these matters.
 
DTC has advised us that DTC is a limited-purpose trust company created to hold securities for its participating organizations (collectively, the “Participants”) and to facilitate the clearance and settlement of transactions in those securities between Participants through electronic book-entry changes in accounts of its Participants. The Participants include securities brokers and dealers (including the underwriters), banks, trust companies, clearing corporations and certain other organizations. Access to DTC’s system is also available to other entities such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a Participant, either directly or indirectly (collectively, the “Indirect Participants”). Persons who are not Participants may beneficially own securities held by or on behalf of DTC only through the Participants or the Indirect Participants. The ownership interests in, and transfers of ownership interests in, each security held by or on behalf of DTC are recorded on the records of the Participants and Indirect Participants.
 
DTC has also advised us that, pursuant to procedures established by it:
 
(1) upon deposit of the Global Notes, DTC will credit the accounts of Participants designated by the underwriters with portions of the principal amount of the Global Notes; and
 
(2) the ownership of these interests in the Global Notes will be shown on, and the transfer of ownership of these interests will be effected only through, records maintained by DTC (with respect to the Participants) or by the Participants and the Indirect Participants (with respect to other owners of beneficial interests in the Global Notes).
 
Investors in the Global Notes who are Participants in DTC’s system may hold their interests therein directly through DTC. Investors in the Global Notes who are not Participants may hold their interests therein indirectly through organizations (including Euroclear and Clearstream) which are Participants in such system. Euroclear and Clearstream may hold interests in the Global Notes on behalf of their participants through


15


Table of Contents

customers’ securities accounts in their respective names on the books of their respective depositories, which are Euroclear Bank S.A./N.V., as operator of Euroclear, and Citibank, N.A., as operator of Clearstream. All interests in a Global Note, including those held through Euroclear or Clearstream, may be subject to the procedures and requirements of DTC. Those interests held through Euroclear or Clearstream may also be subject to the procedures and requirements of such systems.
 
The laws of some states require that certain Persons take physical delivery in definitive form of securities that they own. Consequently, the ability to transfer beneficial interests in a Global Note to such Persons will be limited to that extent. Because DTC can act only on behalf of Participants, which in turn act on behalf of Indirect Participants, the ability of a Person having beneficial interests in a Global Note to pledge such interests to Persons that do not participate in the DTC system, or otherwise take actions in respect of such interests, may be affected by the lack of a physical certificate evidencing such interests.
 
Except as described below, owners of an interest in the Global Notes will not have notes registered in their names, will not receive physical delivery of Certificated Notes and will not be considered the registered owners or “Holders” thereof under the indenture for any purpose.
 
Payments in respect of the principal of, and interest and premium, if any, on a Global Note registered in the name of DTC or its nominee will be payable to DTC in its capacity as the registered Holder under the indenture. Under the terms of the indenture, the Company and the trustee will treat the Persons in whose names the Debt Securities, including the Global Notes, are registered as the owners of the Debt Securities for the purpose of receiving payments and for all other purposes. Consequently, neither the Company, the trustee nor any agent of the Company or the trustee has or will have any responsibility or liability for:
 
(1) upon any aspect of DTC’s records or any Participant’s or Indirect Participant’s records relating to or payments made on account of beneficial ownership interests in the Global Notes or for maintaining, supervising or reviewing any of DTC’s records or any Participant’s or Indirect Participant’s records relating to the beneficial ownership interests in the Global Notes; or
 
(2) any other matter relating to the actions and practices of DTC or any of its Participants or Indirect Participants.
 
DTC has advised us that its current practice, at the due date of any payment in respect of securities such as the Debt Securities, is to credit the accounts of the relevant Participants with the payment on the payment date unless DTC has reason to believe it will not receive payment on such payment date. Each relevant Participant is credited with an amount proportionate to its beneficial ownership of an interest in the principal amount of the Debt Securities as shown on the records of DTC. Payments by the Participants and the Indirect Participants to the beneficial owners of Debt Securities will be governed by standing instructions and customary practices and will be the responsibility of the Participants or the Indirect Participants and will not be the responsibility of DTC, the trustee or the Company. Neither the Company nor the trustee will be liable for any delay by DTC or any of its Participants in identifying the beneficial owners of the Debt Securities, and the Company and the trustee may conclusively rely on and will be protected in relying on instructions from DTC or its nominee for all purposes.
 
Transfers between Participants in DTC will be effected in accordance with DTC’s procedures, and will be settled in same-day funds, and transfers between participants in Euroclear and Clearstream will be effected in accordance with their respective rules and operating procedures.
 
Cross-market transfers between the Participants in DTC, on the one hand, and Euroclear or Clearstream participants, on the other hand, will be effected through DTC in accordance with DTC’s rules on behalf of Euroclear or Clearstream, as the case may be, by its depositary; however, such cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in such system in accordance with the rules and procedures and within the established deadlines (Brussels time) of such system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its respective depositary to take action to effect final settlement on its behalf by delivering or receiving interests in the relevant Global Note in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Euroclear


16


Table of Contents

participants and Clearstream participants may not deliver instructions directly to the depositories for Euroclear or Clearstream.
 
DTC has advised us that it will take any action permitted to be taken by a Holder of Debt Securities only at the direction of one or more Participants to whose account DTC has credited the interests in the Global Notes and only in respect of such portion of the aggregate principal amount of the Debt Securities as to which such Participant or Participants has or have given such direction. However, if there is an Event of Default under the Debt Securities, DTC reserves the right to exchange the Global Notes for Certificated Notes and to distribute such Debt Securities to its Participants.
 
Although DTC, Euroclear and Clearstream have agreed to the foregoing procedures to facilitate transfers of interests in the Global Notes among participants in DTC, Euroclear and Clearstream, they are under no obligation to perform or to continue to perform such procedures, and may discontinue such procedures at any time. None of the Company, the trustee or any of their respective agents will have any responsibility for the performance by DTC, Euroclear or Clearstream or their respective participants or indirect participants of their respective obligations under the rules and procedures governing their operations.
 
Exchange of Global Notes for Certificated Notes
 
A Global Note is exchangeable for Certificated Notes in minimum denominations of $1,000 and in integral multiples of $1,000, if:
 
(1) DTC (a) notifies us that it is unwilling or unable to continue as depositary for the Global Notes or (b) has ceased to be a clearing agency registered under the Exchange Act and in either event the Company fails to appoint a successor depositary within 90 days; or
 
(2) there has occurred and is continuing an Event of Default and DTC notifies the trustee of its decision to exchange the Global Note for Certificated Notes.
 
Certificated Notes delivered in exchange for any Global Note or beneficial interests in Global Notes will be registered in the names, and issued in any approved denominations, requested by or on behalf of the depositary (in accordance with its customary procedures).
 
Same Day Settlement and Payment
 
The Company will make payments in respect of the Debt Securities represented by the Global Notes (including principal, premium, if any, and interest) by wire transfer of immediately available funds to the accounts specified by the Global Note Holder. The Company will make all payments of principal, interest and premium, if any, with respect to Certificated Notes by wire transfer of immediately available funds to the accounts specified by the Holders of the Certificated Notes or, if no such account is specified, by mailing a check to each such Holder’s registered address. The Debt Securities represented by the Global Notes are expected to trade in DTC’s Same-Day Funds Settlement System, and any permitted secondary market trading activity in such Debt Securities will, therefore, be required by DTC to be settled in immediately available funds. The Company expects that secondary trading in any Certificated Notes will also be settled in immediately available funds.
 
Because of time zone differences, the securities account of a Euroclear or Clearstream participant purchasing an interest in a Global Note from a Participant in DTC will be credited, and any such crediting will be reported to the relevant Euroclear or Clearstream participant, during the securities settlement processing day (which must be a business day for Euroclear and Clearstream) immediately following the settlement date of DTC. DTC has advised us that cash received in Euroclear or Clearstream as a result of sales of interests in a Global Note by or through a Euroclear or Clearstream participant to a Participant in DTC will be received with value on the settlement date of DTC but will be available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC’s settlement date.


17


Table of Contents

 
DESCRIPTION OF CAPITAL STOCK
 
The following description of our capital stock summarizes general terms and provisions that apply to our capital stock. Since this is only a summary it does not contain all of the information that may be important to you. The summary is subject to and qualified in its entirety by reference to our certificate of incorporation, by-laws and rights agreement, which are filed as exhibits to the registration statement of which this prospectus is a part and incorporated by reference into this prospectus. See “Where You Can Find More Information.”
 
General
 
The authorized capital stock of Whiting Petroleum Corporation consists of 75,000,000 shares of common stock, $0.001 par value per share, and 5,000,000 shares of preferred stock, $0.001 par value per share. We will disclose in an applicable prospectus supplement and/or offering material the number of shares of our common stock then outstanding. As of the date of this prospectus, no shares of our preferred stock were outstanding.
 
Common Stock
 
Holders of our common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders and do not have cumulative voting rights. Accordingly, holders of a majority of the shares of our common stock entitled to vote in any election of directors may elect all of the directors standing for election. Holders of our common stock are entitled to receive proportionately any dividends if and when such dividends are declared by our board of directors, subject to any preferential dividend rights of outstanding preferred stock. Upon the liquidation, dissolution or winding up of our company, the holders of our common stock are entitled to receive ratably our net assets available after the payment of all debts and other liabilities and subject to the prior rights of any outstanding preferred stock. Holders of our common stock have no preemptive, subscription, redemption or conversion rights. The rights, preferences and privileges of holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.
 
Preferred Stock
 
Under the terms of our certificate of incorporation, our board of directors is authorized to designate and issue shares of preferred stock in one or more series without stockholder approval. Our board of directors has discretion to determine the rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, of each series of preferred stock.
 
Our board of directors has designated 1,500,000 shares of our preferred stock as Series A Junior Participating Preferred Stock in connection with the adoption of our stockholder rights plan, as described below. Each holder of Series A preferred shares will be entitled to a minimum preferential quarterly dividend payment of $1.00 per share, but will be entitled to an aggregate dividend of 100 times the dividend declared per share of our common stock. In the event of liquidation, the holders of the Series A preferred shares will be entitled to a minimum preferential liquidation payment of $100 per share, but will be entitled to an aggregate payment of 100 times the payment made per share of our common stock. Each Series A preferred share will have 100 votes, voting together with shares of our common stock. In the event of any merger, consolidation or other transaction in which shares of our common stock are exchanged, each Series A preferred share will be entitled to receive 100 times the amount received per share of our common stock. As of the date of this prospectus, no shares of our Series A Junior Participating Preferred Stock were outstanding.
 
If we offer preferred stock, we will file the terms of the preferred stock with the SEC and the prospectus supplement and/or other offering material relating to that offering will include a description of the specific terms of the offering, including the following specific terms:
 
  •      the series, the number of shares offered and the liquidation value of the preferred stock;
 
  •      the price at which the preferred stock will be issued;


18


Table of Contents

 
  •      the dividend rate, the dates on which the dividends will be payable and other terms relating to the payment of dividends on the preferred stock;
 
  •      the liquidation preference of the preferred stock;
 
  •      the voting rights of the preferred stock;
 
  •      whether the preferred stock is redeemable or subject to a sinking fund, and the terms of any such redemption or sinking fund;
 
  •      whether the preferred stock is convertible or exchangeable for any other securities, and the terms of any such conversion; and
 
  •      any additional rights, preferences, qualifications, limitations and restrictions of the preferred stock.
 
It is not possible to state the actual effect of the issuance of any shares of preferred stock upon the rights of holders of our common stock until the board of directors determines the specific rights of the holders of the preferred stock. However, these effects might include:
 
  •      restricting dividends on the common stock;
 
  •      diluting the voting power of the common stock;
 
  •      impairing the liquidation rights of the common stock; and
 
  •      delaying or preventing a change in control of our company.
 
Preferred Share Purchase Rights
 
We have entered into a rights agreement pursuant to which each share of our common stock outstanding on March 2, 2006 received a dividend of a right to purchase from us one one-hundredth of a share of our Series A Junior Participating Preferred Stock. Each share of our common stock subsequently issued by us prior to the expiration of the rights agreement will likewise have attached one right. Unless the context requires otherwise, all references in this prospectus to our common stock include the accompanying rights.
 
Currently, the rights are not exercisable and trade with our common stock. If the rights become exercisable, then each full right, unless held by a person or group that beneficially owns more than 15% of our outstanding common stock, will initially entitle the holder to purchase one one-hundredth of a Series A preferred share at a purchase price of $180 per one one-hundredth of a Series A preferred share, subject to adjustment. The rights will become exercisable only if a person or group has acquired, or announced an intention to acquire, 15% or more of our outstanding common stock. Under some circumstances, including the existence of a 15% acquiring party, each holder of a right, other than the acquiring party, will be entitled to purchase at the right’s then-current exercise price, shares of our common stock having a market value of two times the exercise price. If another corporation acquires our company after a party acquires 15% or more of our common stock, then each holder of a right will be entitled to receive the acquiring corporation’s common shares having a market value of two times the exercise price.
 
The rights may be redeemed at a price of $.001 until a party acquires 15% or more of our common stock and, after that time, may be exchanged until a party acquires 50% or more of our common stock at a ratio of one share of common stock, or one one-hundredth of a Series A preferred share, per right, subject to adjustment. Series A preferred shares purchased upon the exercise of rights will not be redeemable. The rights expire on February 23, 2016, subject to extension. Under the rights agreement, our board of directors may reduce the thresholds applicable to the rights from 15% to not less than 10%. The rights do not have voting or dividend rights and, until they become exercisable, have no dilutive effect on our earnings.
 
The rights have certain anti-takeover effects, in that they could have the effect of delaying, deferring or preventing a change of control of our company by causing substantial dilution to a person or group that attempts to acquire a significant interest in our company on terms not approved by our board of directors.


19


Table of Contents

Delaware Anti-Takeover Law and Charter and By-law Provisions
 
We are subject to the provisions of Section 203 of the Delaware General Corporation Law. In general, the statute prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless the business combination or the transaction by which the person became an interested stockholder is approved by the corporation’s board of directors and/or stockholders in a prescribed manner or the person owns at least 85% of the corporation’s outstanding voting stock after giving effect to the transaction in which the person became an interested stockholder. The term “business combination” includes mergers, asset sales and other transactions resulting in a financial benefit to the interested stockholder. Subject to certain exceptions, an “interested stockholder” is a person who, together with affiliates and associates, owns, or within three years did own, 15% or more of the corporation’s voting stock. A Delaware corporation may “opt out” from the application of Section 203 through a provision in its certificate of incorporation or by-laws. We have not “opted out” from the application of Section 203.
 
Under our certificate of incorporation and by-laws, our board of directors is divided into three classes, with staggered terms of three years each. Each year the term of one class expires. Any vacancies on the board of directors may be filled only by a majority vote of the remaining directors. Our certificate of incorporation and by-laws also provide that any director may be removed from office, but only for cause and only by the affirmative vote of the holders of at least 70% of the voting power of our then outstanding capital stock entitled to vote generally in the election of directors.
 
Our certificate of incorporation prohibits stockholders from taking action by written consent without a meeting and provides that meetings of stockholders may be called only by our chairman of the board, our president or a majority of our board of directors. Our by-laws further provide that nominations for the election of directors and advance notice of other action to be taken at meetings of stockholders must be given in the manner provided in our by-laws, which contain detailed notice requirements relating to nominations and other action.
 
The foregoing provisions of our certificate of incorporation and by-laws and the provisions of Section 203 of the Delaware General Corporation Law could have the effect of delaying, deferring or preventing a change of control of our company.
 
Liability and Indemnification of Officers and Directors
 
Our certificate of incorporation provides that our directors will not be personally liable to us or our stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (1) for any breach of a director’s duty of loyalty to us or our stockholders, (2) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (3) under Section 174 of the Delaware General Corporation Law, or (4) for any transaction from which the director derives an improper personal benefit. Moreover, the provisions do not apply to claims against a director for violations of certain laws, including federal securities laws. If the Delaware General Corporation Law is amended to authorize the further elimination or limitation of directors’ liability, then the liability of our directors will automatically be limited to the fullest extent provided by law. Our certificate of incorporation and by-laws also contain provisions to indemnify our directors and officers to the fullest extent permitted by the Delaware General Corporation Law. In addition, we may enter into indemnification agreements with our directors and officers. These provisions and agreements may have the practical effect in certain cases of eliminating the ability of stockholders to collect monetary damages from our directors and officers. We believe that these contractual agreements and the provisions in our certificate of incorporation and by-laws are necessary to attract and retain qualified persons as directors and officers.
 
Transfer Agent and Registrar
 
The transfer agent and registrar for our common stock is Computershare Trust Company, Inc.


20


Table of Contents

 
DESCRIPTION OF WARRANTS
 
We may issue warrants for the purchase of debt securities, preferred stock, common stock or other securities. Warrants may be issued independently or together with debt securities, preferred stock or common stock offered by any prospectus supplement and/or other offering material and may be attached to or separate from any such offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent, all as will be set forth in the prospectus supplement and/or other offering material relating to the particular issue of warrants. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any holders of warrants or beneficial owners of warrants.
 
The following summary of certain provisions of the warrants does not purport to be complete and is subject to, and is qualified in its entirety by reference to, all provisions of the warrant agreements.
 
Reference is made to the prospectus supplement and/or other offering material relating to the particular issue of warrants offered pursuant to such prospectus supplement and/or other offering material for the terms of and information relating to such warrants, including, where applicable:
 
  •      the designation, aggregate principal amount, currencies, denominations and terms of the series of debt securities purchasable upon exercise of warrants to purchase debt securities and the price at which such debt securities may be purchased upon such exercise;
 
  •      the number of shares of common stock purchasable upon the exercise of warrants to purchase common stock and the price at which such number of shares of common stock may be purchased upon such exercise;
 
  •      the number of shares and series of preferred stock purchasable upon the exercise of warrants to purchase preferred stock and the price at which such number of shares of such series of preferred stock may be purchased upon such exercise;
 
  •      the designation and number of units of other securities purchasable upon the exercise of warrants to purchase other securities and the price at which such number of units of such other securities may be purchased upon such exercise;
 
  •      the date on which the right to exercise such warrants shall commence and the date on which such right shall expire;
 
  •      United States federal income tax consequences applicable to such warrants;
 
  •      the amount of warrants outstanding as of the most recent practicable date; and
 
  •      any other terms of such warrants.
 
Warrants will be issued in registered form only. The exercise price for warrants will be subject to adjustment in accordance with the applicable prospectus supplement and/or other offering material.
 
Each warrant will entitle the holder thereof to purchase such principal amount of debt securities or such number of shares of preferred stock, common stock or other securities at such exercise price as shall in each case be set forth in, or calculable from, the prospectus supplement and/or other offering material relating to the warrants, which exercise price may be subject to adjustment upon the occurrence of certain events as set forth in such prospectus supplement and/or other offering material. After the close of business on the expiration date, or such later date to which such expiration date may be extended by us, unexercised warrants will become void. The place or places where, and the manner in which, warrants may be exercised shall be specified in the prospectus supplement and/or other offering material relating to such warrants.
 
Prior to the exercise of any warrants to purchase debt securities, preferred stock, common stock or other securities, holders of such warrants will not have any of the rights of holders of debt securities, preferred stock, common stock or other securities, as the case may be, purchasable upon such exercise, including the right to receive payments of principal of, premium, if any, or interest, if any, on the debt securities purchasable upon such exercise or to enforce covenants in the applicable Indenture, or to receive payments of dividends, if


21


Table of Contents

any, on the preferred stock, or common stock purchasable upon such exercise, or to exercise any applicable right to vote.
 
DESCRIPTION OF STOCK PURCHASE CONTRACTS AND STOCK PURCHASE UNITS
 
We may issue stock purchase contracts, including contracts obligating holders to purchase from us, and obligating us to sell to the holders, a specified number of shares of common stock or other securities at a future date or dates, which we refer to in this prospectus as “stock purchase contracts.” The price per share of the securities and the number of shares of the securities may be fixed at the time the stock purchase contracts are issued or may be determined by reference to a specific formula set forth in the stock purchase contracts. The stock purchase contracts may be issued separately or as part of units consisting of a stock purchase contract and debt securities, preferred securities, warrants, other securities or debt obligations of third parties, including U.S. treasury securities, securing the holders’ obligations to purchase the securities under the stock purchase contracts, which we refer to herein as “stock purchase units.” The stock purchase contracts may require holders to secure their obligations under the stock purchase contracts in a specified manner. The stock purchase contracts also may require us to make periodic payments to the holders of the stock purchase units or vice versa, and those payments may be unsecured or refunded on some basis.
 
The stock purchase contracts, and, if applicable, collateral or depositary arrangements, relating to the stock purchase contracts or stock purchase units, will be filed with the SEC in connection with the offering of stock purchase contracts or stock purchase units. The prospectus supplement and/or other offering material relating to a particular issue of stock purchase contracts or stock purchase units will describe the terms of those stock purchase contracts or stock purchase units, including the following:
 
  •      if applicable, a discussion of material United States federal income tax considerations; and
 
  •      any other information we think is important about the stock purchase contracts or the stock purchase units.
 
WHERE YOU CAN FIND MORE INFORMATION
 
We file annual, quarterly and current reports, proxy statements and other information with the SEC. We also filed a registration statement on Form S-3, including exhibits, under the Securities Act of 1933 with respect to the securities offered by this prospectus. This prospectus is a part of the registration statement, but does not contain all of the information included in the registration statement or the exhibits. You may read and copy the registration statement and any other document that we file at the SEC’s public reference room at 100 F Street, N.E., Washington D.C. 20549. You can call the SEC at 1-800-SEC-0330 for further information on the operation of the public reference room. You can also find our public filings with the SEC on the internet at a web site maintained by the SEC located at http://www.sec.gov.
 
We are “incorporating by reference” specified documents that we file with the SEC, which means:
 
  •      incorporated documents are considered part of this prospectus;
 
  •      we are disclosing important information to you by referring you to those documents; and
 
  •      information we file with the SEC will automatically update and supersede information contained in this prospectus.
 
We incorporate by reference the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 after the date of this prospectus and before the end of the offering of the securities pursuant to this prospectus:
 
  •      our Annual Report on Form 10-K for the year ended December 31, 2005;
 
  •      our Quarterly Report on Form 10-Q for the quarter ended March 31, 2006;
 
  •      our Current Reports on Form 8-K, dated February 23, 2006;


22


Table of Contents

 
  •      the description of our common stock contained in our Registration Statement on Form 8-A, dated November 14, 2003, and any amendment or report updating that description; and
 
  •      the description of our preferred share purchase rights contained in our Registration Statement on Form 8-A, dated February 24, 2006 and any amendment or report updating that description.
 
You may request a copy of any of these filings, at no cost, by request directed to us at the following address or telephone number:
 
      Whiting Petroleum Corporation
1700 Broadway, Suite 2300
Denver, Colorado 80290
(303) 837-1661
Attention: Corporate Secretary
 
You can also finds these filings on our website at www.whiting.com. However, we are not incorporating the information on our website other than these filings into this prospectus.
 
PLAN OF DISTRIBUTION
 
We may sell our securities, and any selling stockholder may sell shares of our common stock, in any one or more of the following ways from time to time: (i) through agents; (ii) to or through underwriters; (iii) through brokers or dealers; (iv) directly by us or any selling stockholders to purchasers, including through a specific bidding, auction or other process; or (v) through a combination of any of these methods of sale. The applicable prospectus supplement and/or other offering material will contain the terms of the transaction, name or names of any underwriters, dealers, agents and the respective amounts of securities underwritten or purchased by them, the initial public offering price of the securities, and the applicable agent’s commission, dealer’s purchase price or underwriter’s discount. Any selling stockholders, dealers and agents participating in the distribution of the securities may be deemed to be underwriters, and compensation received by them on resale of the securities may be deemed to be underwriting discounts. Additionally, because selling stockholders may be deemed to be “underwriters” within the meaning of Section 2(11) of the Securities Act, selling stockholders may be subject to the prospectus delivery requirements of the Securities Act.
 
Any initial offering price, dealer purchase price, discount or commission may be changed from time to time.
 
The securities may be distributed from time to time in one or more transactions, at negotiated prices, at a fixed or fixed prices (that may be subject to change), at market prices prevailing at the time of sale, at various prices determined at the time of sale or at prices related to prevailing market prices.
 
Offers to purchase securities may be solicited directly by us or any selling stockholder or by agents designated by us from time to time. Any such agent may be deemed to be an underwriter, as that term is defined in the Securities Act, of the securities so offered and sold.
 
If underwriters are utilized in the sale of any securities in respect of which this prospectus is being delivered, such securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at fixed public offering prices or at varying prices determined by the underwriters at the time of sale. Securities may be offered to the public either through underwriting syndicates represented by managing underwriters or directly by one or more underwriters. If any underwriter or underwriters are utilized in the sale of securities, unless otherwise indicated in the applicable prospectus supplement and/or other offering material, the obligations of the underwriters are subject to certain conditions precedent and that the underwriters will be obligated to purchase all such securities if any are purchased.
 
If a dealer is utilized in the sale of the securities in respect of which this prospectus is delivered, we will sell such securities, and any selling stockholder will sell shares of our common stock to the dealer, as principal. The dealer may then resell such securities to the public at varying prices to be determined by such


23


Table of Contents

dealer at the time of resale. Transactions through brokers or dealers may include block trades in which brokers or dealers will attempt to sell shares as agent but may position and resell as principal to facilitate the transaction or in crosses, in which the same broker or dealer acts as agent on both sides of the trade. Any such dealer may be deemed to be an underwriter, as such term is defined in the Securities Act, of the securities so offered and sold. In addition, any selling stockholder may sell shares of our common stock in ordinary brokerage transactions or in transactions in which a broker solicits purchases.
 
Offers to purchase securities may be solicited directly by us or any selling stockholder and the sale thereof may be made by us or any selling stockholder directly to institutional investors or others, who may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale thereof.
 
Any selling stockholders may also resell all or a portion of their shares of our common stock in transactions exempt from the registration requirements of the Securities Act in reliance upon Rule 144 under the Securities Act provided they meet the criteria and conform to the requirements of that rule, Section 4(1) of the Securities Act or other applicable exemptions, regardless of whether the securities are covered by the registration statement of which this prospectus forms a part.
 
If so indicated in the applicable prospectus supplement and/or other offering material, we or any selling stockholder may authorize agents and underwriters to solicit offers by certain institutions to purchase securities from us or any selling stockholder at the public offering price set forth in the applicable prospectus supplement and/or other offering material pursuant to delayed delivery contracts providing for payment and delivery on the date or dates stated in the applicable prospectus supplement and/or other offering material. Such delayed delivery contracts will be subject only to those conditions set forth in the applicable prospectus supplement and/or other offering material.
 
Agents, underwriters and dealers may be entitled under relevant agreements with us or any selling stockholder to indemnification by us against certain liabilities, including liabilities under the Securities Act, or to contribution with respect to payments which such agents, underwriters and dealers may be required to make in respect thereof. The terms and conditions of any indemnification or contribution will be described in the applicable prospectus supplement and/or other offering material. We may pay all expenses incurred with respect to the registration of the shares of common stock owned by any selling stockholders, other than underwriting fees, discounts or commissions, which will be borne by the selling stockholders.
 
We or any selling stockholder may also sell shares of our common stock through various arrangements involving mandatorily or optionally exchangeable securities, and this prospectus may be delivered in connection with those sales.
 
We or any selling stockholder may enter into derivative, sale or forward sale transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement and/or other offering material indicates, in connection with those transactions, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement and/or other offering material, including in short sale transactions and by issuing securities not covered by this prospectus but convertible into or exchangeable for or represents beneficial interests in such securities, or the return of which is derived in whole or in part from the value of such securities. If so, the third party may use securities received under those sale, forward sale or derivative arrangements or securities pledged by us or any selling stockholder or borrowed from us, any selling stockholder or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us or any selling stockholder in settlement of those transactions to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement (or a post-effective amendment) and/or other offering material.
 
Additionally, any selling stockholder may engage in hedging transactions with broker-dealers in connection with distributions of shares or otherwise. In those transactions, broker-dealers may engage in short sales of shares in the course of hedging the positions they assume with such selling stockholder. Any selling stockholder also may sell shares short and redeliver shares to close out such short positions. Any selling stockholder may also enter into option or other transactions with broker-dealers which require the delivery of


24


Table of Contents

shares to the broker-dealer. The broker-dealer may then resell or otherwise transfer such shares pursuant to this prospectus. Any selling stockholder also may loan or pledge shares, and the borrower or pledgee may sell or otherwise transfer the shares so loaned or pledged pursuant to this prospectus. Such borrower or pledgee also may transfer those shares to investors in our securities or the selling stockholder’s securities or in connection with the offering of other securities not covered by this prospectus.
 
Underwriters, broker-dealers or agents may receive compensation in the form of commissions, discounts or concessions from us or any selling stockholder. Underwriters, broker-dealers or agents may also receive compensation from the purchasers of shares for whom they act as agents or to whom they sell as principals, or both. Compensation as to a particular underwriter, broker-dealer or agent might be in excess of customary commissions and will be in amounts to be negotiated in connection with transactions involving shares. In effecting sales, broker-dealers engaged by us or any selling stockholder may arrange for other broker-dealers to participate in the resales.
 
Each series of securities will be a new issue and, other than the common stock, which is listed on the New York Stock Exchange, will have no established trading market. We may elect to list any series of securities on an exchange, and in the case of the common stock, on any additional exchange, but, unless otherwise specified in the applicable prospectus supplement and/or other offering material, we shall not be obligated to do so. No assurance can be given as to the liquidity of the trading market for any of the securities.
 
Agents, underwriters and dealers may engage in transactions with, or perform services for us or any selling stockholder and our respective subsidiaries in the ordinary course of business.
 
Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation M under the Securities Exchange Act of 1934. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. An underwriter may carry out these transactions on the New York Stock Exchange, in the over-the-counter market or otherwise.
 
The place and time of delivery for securities will be set forth in the accompanying prospectus supplement and/or other offering material for such securities.
 
LEGAL MATTERS
 
The validity of the securities offered by this prospectus will be passed upon for us by Foley & Lardner LLP. The validity of the securities offered by this prospectus will be passed upon for any underwriters or agents by counsel named in the applicable prospectus supplement. The opinions of Foley & Lardner LLP and counsel for any underwriters or agents may be conditioned upon and may be subject to assumptions regarding future action required to be taken by us and any underwriters, dealers or agents in connection with the issuance of any securities. The opinions of Foley & Lardner LLP and counsel for any underwriters or agents may be subject to other conditions and assumptions, as indicated in the prospectus supplement.
 
EXPERTS
 
The financial statements, financial statement schedule, and management’s report on the effectiveness of internal control over financial reporting incorporated in this prospectus by reference from Whiting Petroleum Corporation’s Annual Report on Form 10-K for the year ended December 31, 2005 have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference (which reports (1) express an unqualified opinion on the financial


25


Table of Contents

statements and financial statement schedule and include an explanatory paragraph referring to a change in Whiting Petroleum Corporation’s method of accounting for asset retirement obligations effective January 1, 2003, (2) express an unqualified opinion on management’s assessment regarding the effectiveness of internal control over financial reporting, and (3) express an unqualified opinion on the effectiveness of internal control over financial reporting) and have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.
 
Certain information with respect to our oil and natural gas reserves derived from the reports of Cawley Gillespie & Associates, Inc., R.A. Lenser & Associates, Inc., Ryder Scott Company, L.P. and Netherland, Sewell & Associates, Inc., each independent petroleum engineering consultants, has been incorporated in this prospectus by reference from Whiting Petroleum Corporation’s Annual Report on Form 10-K for the year ended December 31, 2005 on the authority of said firms as experts in petroleum engineering.


26


Table of Contents


Table of Contents


Table of Contents


Table of Contents

 
8,000,000 Shares
 
(WHITING LOGO)
Whiting Petroleum Corporation
 
Common Stock
 
 
PROSPECTUS SUPPLEMENT
 
 
 
Merrill Lynch & Co.
J.P.Morgan
Raymond James
Barclays Capital
KeyBanc Capital Markets
Wachovia Securities
Jefferies & Company
RBC Capital Markets
Tristone Capital
 
          , 2009