Rex Energy Corporation is an independent oil, natural gas liquid (NGL) and natural gas company operating in the Appalachian Basin and Illinois Basin. In the Appalachian Basin, the Company is focused on its Marcellus Shale, Utica Shale and Upper Devonian Shale drilling and exploration activities. In the Illinois Basin, it is focused on developmental oil drilling and the implementation of enhanced oil recovery on its properties. It operates in two segments, Exploration and Production, and Field Services. The Exploration and Production segment is involved in the acquisition, development, exploration, and production of oil, natural gas, and natural gas liquids. The Field services segment provides oil and gas field services comprising water sourcing, water transfer, and water disposal services, as well as equipment rental primarily in the Appalachian Basin. As of December 31, 2013, it operated approximately 1,799 oil and natural gas wells.