Rex Energy Corporation was a natural gas exploration and production company headquartered in State College, Pennsylvania. In 2018, the company was acquired by PennEnergy Resources. The company's operations were entirely in the Appalachian Basin, in the Marcellus Shale, Utica Shale, and the Burkett Shale. The company primarily extracted resources using hydraulic fracturing. As of December 31, 2016, the company had 108 million barrels of oil equivalent (660,000,000 GJ) of estimated proved reserves, of which 56.8% was natural gas, 41.5% was natural gas liquids, and 1.7% was natural-gas condensate. In 2016, the company's production was 195 million cubic feet of natural gas equivalent per day.