Oil steadied below $49 a barrel as U.S. drillers continued to boost activity, countering OPEC’s efforts to drain a global glut.

Crude prices could plunge toward $30 a barrel — a rout of about 40% from current levels — unless OPEC extends production cuts that are propping up the market, ABN Amro Bank NV said.

Shale wildcatters pushed ahead on the biggest surge in U.S. oil drilling since 2012 as explorers take advantage of prices above $50 for more than two months.

Oil traded near the highest since July last year amid optimism OPEC and 11 other producing nations will cut output as promised, helping eliminate a global supply glut.

Oil retreated from a 16-month high after OPEC pumped a record amount of crude in November.

OPEC’s first production cuts in eight years are intended to shrink the world’s bloated oil stockpiles back to a normal level, paving the way for prices to rise to more than $60 a barrel.

OPEC clinched a deal to curtail oil supply, confounding skeptics as the need to clear a record global crude glut — and prove the group’s credibility — brought its first cuts in eight years.

The world should get used to oil prices between $50 and $60 a barrel as falling costs in America’s shale fields counteract OPEC’s renewed commitment to supply management.

OPEC agreed to cut production for the first time in eight years, according to a delegate briefed on the matter, sending oil prices more than 6% higher as Saudi Arabia and Iran wrong-footed traders who expected a continuation of the pump-at-will policy the group adopted in 2014.

The surplus in global oil markets will last for longer than previously thought, persisting into late 2017 as demand growth slumps and supply proves resilient, the International Energy Agency reported.