Pioneer Natural Resources Co. (NYSE: PXD) and Pioneer Southwest Energy Partners LP are merging.

Under the terms of the deal, Pioneer Southwest would become a wholly-owned subsidiary of Pioneer Natural’s operating company, Pioneer Natural Resources USA Inc.

Pioneer Southwest’s stockholders would receive 0.2325 per share of Pioneer Natural common stock for each of its shares given to Pioneer Natural.

Evercore Partners acted as financial adviser to Pioneer Southwest’s conflicts committee, which approved the deal, in connection with the transaction.

Pioneer Natural, headquartered in Dallas, is an oil and gas exploration company. Pioneer Southwest, also based in Dallas, has drilling operations in the Spraberry field in west Texas.

Other recent oil and gas deals include Exco Resources Inc.’s (NYSE: XCO) purchase of undeveloped oil and gas assets in the Eagle Ford and Haynesville shale formations for $1 billion, and First Reserve Corp.’s $500 million investment to form Century Midstream LLC