The number of U.S. drilling rigs in use fell sharply in the week to Friday, almost doubling the cuts of the past two weeks and hitting the lowest since April 2011, a survey showed.
The number of rigs drilling for oil in the United States fell by 64 to 922, oil services company Baker Hughes Inc said in its weekly report.
"The drop in the oil rig count was a little more than expected, as we thought the velocity of declines had slowed," said Evercore ISI analyst James West.
The reduction this week almost doubled declines of 33 and 37 in the prior two weeks. But those declines were less steep than those of the prior three weeks, which exceeded 80.
Rigs fell for the 13th straight week as producers cut activity in the face of slumping oil prices. The number of oil rigs in use has fallen in 18 of the past 21 weeks, according to Baker Hughes.
The rig count has fallen at the quickest rate on record over the past four months, dropping more than 40 percent from a record high of 1,609 in October.
Texas, the state with the most rigs, again lost the most this week, shedding 32 to 537, the lowest since 2010, Baker Hughes said.
The shale play with the biggest losses was Permian in West Texas and New Mexico, the nation's biggest and fastest growing shale oil play.
The Permian lost 24 oil rigs to 328, the least since 2011, according to data going back to 2011.
Horizontal rigs, the most efficient type of rig most often used to extract oil or gas from shale, fell by 51 to 895, the lowest since 2010.
Less efficient vertical and directional rigs, meanwhile, fell to the lowest since 1991 and 1993, respectively, according to data going back to 1991.
(Reporting by Scott DiSavino; Editing by Peter Galloway, Marguerita Choy, Chris Reese, Lisa Von Ahn and James Dalgleish)