Chesapeake Energy, based in Oklahoma City, explores for, produces, and markets natural gas, oil, and natural gas liquids in the U.S. It focuses on unconventional plays, with large positions in the Barnett, Eagle Ford, Haynesville, Utica, and Marcellus shales, as well as leasehold in a number of liquids-rich basins. Chesapeake controls close to 8 million net acres across its properties. At year-end 2015, the firm's proven reserves totaled 9 trillion cubic feet equivalent, with daily production of 4.1 Bcfe. Natural gas made up 72% of production.