BP Plc ( BP.L ) has agreed to buy U.S. shale oil and gas assets from global miner BHP Billiton ( BLT.L ) ( BHP.AX ) for $10.5 billion, expanding the British oil major’s footprint in oil-rich onshore basins in its biggest deal in nearly 20 years. The acquisition marks a big turning point for BP since the Deepwater Horizon rig disaster in the Gulf of Mexico in 2010, for which the company is still paying off more than $65 billion in penalties and clean-up costs. “This is a transformational acquisition for our Lower 48 business, a major step in delivering our upstream strategy and a world-class addition to BP’s distinctive portfolio,” BP […]