UPDATE 1-U.S. drillers add the most oil rigs since April 2013 -Baker Hughes

(Adds rigs in the Permian and Cana Woodford basins in paragraphs 5-6, total oil and gas rig count in paragraph 12) Jan 20 (Reuters) - U.S. energy companies this week added the most oil rigs in nearly four years, extending an eight-month recovery as drillers take advantage of a deal by OPEC to cut supplies that has boosted prices over $50 a barrel since early December. Drillers added 29 oil rigs in the week to Jan. 20, bringing the total count up to 551, the most since November 2015, e