US shale surge challenges Opec's tightening grip on oil markets

The Organization of Petroleum Exporting Countries (Opec)'s one-time nemesis US shale - is rearing its head just months after the sector was all but written off as a threat to the cartel's sway over worldwide oil markets.

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Drillers from the Permian Basin in West Texas to the Bakken Shale of North Dakota have ramped up oil production well beyond what analysts foresaw, pushing output to a record just as Opec and its allies put the brakes on supplies in a bid to arrest price declines.

This time last year, US government forecasters predicted domestic production would average 12.5 million barrels a day during the current quarter. In recent days, that estimate was bumped to 13.3 million; the difference is equivalent to adding a new Venezuela to global supplies.

That growth is reverberating around the world, calling into question the Opec+ group's strategy of curbing supplies to prevent the potentially catastrophic price impacts of a glut. It also makes clear that the legions of companies that pump oil from US shale fields still wield enough power to bedevil the cartel's efforts.