"We're not collecting cash on the balance sheet to do some sort of M&A." Chesapeake Energy. Merger talk is also active in Appalachia, a giant shale gas formation in the Northeastern US. Chesapeake Energy Corp. is considering a deal to buy rival natural gas producer Southwestern Energy Co., Bloomberg News reported last week. Chesapeake and Southwestern are two of the biggest players in Appalachia. They also operate in the Haynesville, another gas basin in Louisiana, along the Texas border.