Energen develops, acquires, explores for, and produces oil, natural gas, and natural gas liquids across the continental US. The oil and gas exploration and production company operates principally through Energen Resources Corporation, which in 2015 had proved reserves of 355 million barrels of oil equivalent, mainly located in the Permian Basin (West Texas). Oil accounted for 49% of the company’s proved reserves; natural gas, 31%; and natural gas liquids, 20%. In 2014 Energen exited the gas utility business, selling Alabama Gas Corporation (Alagasco) to Spire Inc. for $1.6 billion.