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The US "rig count" - suddenly the most-watched indicator in global energy - has fallen from 1,608 in October to 747 last week. Yet output has to continued to rise, stabilizing only over the past five weeks.
Mr Tillerson said this is more or less what happened in the sister market for US shale gas. In 2009, some 1,200 rigs produced 5.5bn cubic feet (bcf) of gas per day at a market price near $8.
Today the price is just $2.50. Nobody would have believed back then that the industry would continue boosting supply to 7.3 bcf, and be able to do so with just 280 rigs.
"Will we see the same phenomenon in five years in tight oil? I don't know, but this is a very resilient industry. I think people will be surprised,” Mr Tillerson said, speaking at the IHS CERAWeek forum in Houston.
"We've really only begun to scratch the surface. Shale can keep growing by 500,000 to 700,000 b/d easily," said Harold Hamm, founder of Continental Resources. His company has cut costs by 20pc to 25pc over the past four months.
US shale will "roll over" to some degree as producers exhaust their one-year hedges and face the full shock of lower prices. But it is hazardous to bet too heavily on this assumption.
IHS said an astonishing thing is happening as frackers keep discovering cleverer ways to extract oil, and switch tactically to better wells. Costs may plummet by 45pc this year, and by 60pc to 70pc before the end of 2016. "Break-even prices are going down across the board," said the group's Raoul LeBlanc.
Shale bosses have been lining up at this year's "Energy Davos" to proclaim the fracking Gospel. "We have just drilled an 18,000 ft well in 16 days in the Permian Basis. Last year it took 30 days," said Scott Sheffield, head of Pioneer Natural Resources.