Marcellus shale gas unconventional play
The Marcellus Shale is the dominant unconventional play in the Northeast region and the most productive shale gas play in the US Lower 48. The southwest Marcellus includes the counties of Greene, Fayette, and Washington in Pennsylvania, of which Washington County is considered the core. The southwest area produces richer gas. The most active operators are pure players EQT Corporation, Cabot Oil & Gas, Southwestern Energy, and Antero Resources.