SM Energy Company is an independent energy company based in Denver, Colorado, that acquires, explores, develops, and produces oil, natural gas, and natural gas liquids mainly in Texas. It has an estimated 492.0 million barrels of oil equivalent of proved reserves and working interests in 825 gross productive oil wells and 483 gross productive gas wells in the Midland Basin and South Texas. The company, previously known as St. Mary Land & Exploration Company, has been operational since 1908.