The London-based company is working with Morgan Stanley to advise on the plans, said the people, asking not to be identified as the matter is private. BP is weighing teaming up with other suitors or swapping conventional assets -- where oil and gas typically flow more easily to the surface than shale -- with BHP, they said.

No final decisions have been made and BP could decide against proceeding with a formal bid, the people said. Spokesmen for BP, BHP and Morgan Stanley declined to comment on the sale.

BHP is selling 800,000 net acres in the Eagle Ford, Permian, Haynseville and Fayetteville basins it has said are worth at least $10 billion. It is preparing to sell those assets in up to seven packages, including three in highly-prized Permian, people familiar with the matter said this month. It’s not clear which of those assets BP wants to buy.