Southwestern Energy Company is an independent energy company engaged in natural gas and oil exploration, development and production. It is focused on creating and capturing additional value through its natural gas gathering and marketing businesses, which it refers to as Midstream Services. Its primary business is the exploration for and production of natural gas and oil, with operations being focused within the United States on development of an unconventional gas reservoir located on the Arkansas side of the Arkoma Basin, which it refers to as the Fayetteville Shale play. It is also engaged in exploration and production activities in Pennsylvania, and Texas and in Arkansas and Oklahoma in the Arkoma Basin. It conducts its exploration and production operations through its wholly owned subsidiaries, SEECO, Inc., and Southwestern Energy Production Company. In May 2011, it sold the producing rights to the Haynesville and Middle Bossier Shale intervals in approximately 9,717 net acres.