The number of rigs exploring for oil and natural gas in the U.S. rose by 10 this week to 857.
A year ago, 431 rigs were active.
Houston oilfield services company Baker Hughes Inc. said Friday that 688 rigs sought oil and 167 explored for natural gas this week. Two were listed as miscellaneous.
Texas added six rigs and Alaska, Colorado, North Dakota, Pennsylvania and Wyoming each gained one.
Oklahoma lost one rig.
Arkansas, California, Kansas, Louisiana, New Mexico, Ohio, Utah and West Virginia were unchanged.