Pioneer Southwest Energy Partners L.P.

Pioneer Southwest Energy Partners L.P. owns, acquires, explores, and develops oil and gas properties in the United States. It produces oil, natural gas liquids, and gas in onshore Texas and eight counties in the southeast region of New Mexico. The company has non-operated working interests in proved and unproved oil and gas properties in the Spraberry field in the Permian Basin area of West Texas, including 2,408 producing wells. As of December 31, 2012, its total proved oil and gas reserves were 49 million barrels oil equivalent. The company was founded in 2007 and is based in Irving, Texas. Pioneer Southwest Energy Partners L.P. operates as a subsidiary of Pioneer Natural Resources Company.