Devon Energy, based in Oklahoma City, is one of the largest independent exploration & production companies in North America. The firm's asset base includes 6.2 million net acres of conventional and unconventional oil and natural gas properties throughout the U.S. and Canada. At year-end 2015, Devon's proved reserves totaled 11.2 Tcfe, with production of 4.1 Bcfe/d. Natural gas made up 39% of production and 47% of reserves. Midstream and marketing operations accounted for approximately 20% of company-wide EBITDA in 2015.