U.S. crude oil production surged by about 100,000 barrels a day last week, providing further evidence that American drillers are responding quickly to the higher prices that OPEC created by agreeing to curtail their own production.
The Organization of Petroleum Exporting Countries reached an agreement to cut production by 1.2 million barrels a day last month and got commitments from some nonmembers to 558,000 barrels a day in reductions this past weekend. Hopes for output limits had boosted prices ahead of the agreements.
American drillers were not among the nonmembers who agreed to cut. In the lower 48 states, they drove production to nearly 8.8 million barrels a day in the week through Dec. 9, according to the U.S. Energy Information Administration. That is up from about 8.7 million barrels a day the week prior.
To be sure, the weekly production figures are preliminary, and big jumps are not too rare. But a steadily rising four-week average for U.S. oil output points to an overall recovery. At 8.72 million barrels a day, the average was at its highest level since June.
Analysts warn that OPEC's bid to balance an oversupplied market by cutting production could backfire if it causes oil prices to rise too much. Those higher prices could cause U.S. drillers sidelined by low oil prices to start pumping more oil.
The weekly jump in U.S. output is a "major concern" for OPEC members, said John Kilduff, founding partner at energy hedge fund Again Capital.
"This is exactly what several of them had been worried about. This deal gave new life to the shale industry," he told CNBC. "OPEC's going to have its hands full with them for a time."
Recent hedging activity has allowed drillers to lock in prices for future deliveries of oil at $55 a barrel, a price that makes more of their acreage profitable, according to Kilduff, who has been bearish on oil prices and skeptical of OPEC's ability to enforce production cuts.
The production surge follows an increase in the U.S. oil rig count of 21 rigs — the biggest one-week jump since a recovery in drilling activity began in June. Drillers have added a net 182 rigs since the count bottomed out at 316 rigs in May, according to data provided by oilfield services firm Baker Hughes.
The total U.S. rig count stood at 498 at last count, close the year-ago count of 524 rigs.