BHP paid $US20 billion ($A26 billion) for its assets in the emerging US shale space in 2011, its biggest transaction with the Billiton merger in 2001, but over the last year it has increasingly focused on its conventional assets. Now that the company is bedding down to spin-off most of the old Billiton assets as South 32, it is reconsidering its commitments to the US shale space.

Soon after snapping up its assets from Petrohawk Energy in 2011, BHP was hit by a plunging gas price caused by oversupply. It dramatically reduced its exposure to drilling costs in the Fayetteville and Haynesville shales in favour of targeting oilier plays, such as the Eagle Ford Shale, where it could get returns of better than 20% on drilling.

But over time it reduced its shale-seeking budget from around $4 billion per annum expected late last year.

Mackenzie told his audience i