Formed about 380 million years ago, the Marcellus Shale is a deep geologic formation that covers more than 95,000 square miles through parts of New York, Pennsylvania, Ohio and West Virginia. Pennsylvania is at the heart of the Marcellus Shale, with the formation underlying about 60 percent of the state. Once thought to be played out, it is now estimated to hold 168-516 TCF still available with horizontal drilling. It has been suggested that the Marcellus shale and other Devonian shales of the Appalachian Basin, could supply the northeast U.S. with natural gas.

The Marcellus Shale is a unit of marine sedimentary rock found in eastern North America. Named for a distinctive outcrop near the village of Marcellus, New York, it extends throughout much of the Appalachian Basin. The shale contains largely untapped natural gas reserves, and its proximity to the high-demand markets along the East Coast of the United States makes it an attractive target for energy development.

The Marcellus is found between 4,000 and 8,500 feet below the surface and is 50-200 feet thick. This shale formation is rich in organic materials from plants and animals. As these organics were compressed by millions of years of geologic pressures, natural gas was trapped in the shale’s fractures. Even if only 10 percent of the gas is recovered, it would be enough to fuel the entire United States for two years and would be worth over $1 trillion.

Companies drilling:

AB Resources LLC
Adams Resources & Energy, Inc.
Alta Mesa Holdings, LP
Alta Resources, LLC
Anadarko Petroleum Corporation
Anschutz Exploration Corporation
Antero Resources Corp.
Aruba Petroleum, Inc.
Atlas Energy, L.P.
BG Group PLC
Cabot Oil & Gas Corporation
Carrizo Oil & Gas Inc.
Chesapeake Energy Corporation
Chevron Corp.
Chief Oil & Gas, LLC
Citrus Energy Corporation
CNX Gas Corporation
Collins and Young LLC
Consol Energy Inc.
Continental Resources, Inc.
Dale Resources L.L.C.
Denex Petroleum Corp.
Dorchester Minerals, L.P.
Endeavour International Corporation
Energen Resources
Energy Corporation of America
Enerplus Resources
Enervest Ltd
EOG Resources, Inc.
Epsilon Energy Ltd.
EQT Corporation
EV Energy Partners, L.P.
EXCO Resources, Inc.
Gastar Exploration , Ltd.
Gastem, Inc.
GFI Oil & Gas
Goodrich Petroleum Corporation
Hess Corporation
Huntley & Huntley, Inc.
J-W Operating Company
J.F. Deem Oil and Gas
Keeton Group LLC
Little Pine Resources
Magnum Hunter Resources Corp.
Marathon Oil Corporation
Mesa Energy Holdings Inc.
Mid-East Oil Company
Mountain V Oil & Gas, Inc.
National Fuel Gas Company
Newark Energy LLC
Newfield Exploration Co.
Noble Energy, Inc.
Norse Energy Corporation
Novus Operating LLC
PDC Energy, Inc.
Penn Virginia Oil & Gas
Penneco Oil Company Inc.
Pennsylvania General Energy Co., LLC
PetroEdge Energy LLC
Phillips Energy Partners
PostRock Energy Corp.
Range Resources Corporation
Regal Resources Inc.
Reliance Industries Ltd.
Republic Energy, Inc.
Rex Energy Corporation
Rice Energy LP
Running Foxes Petroleum
Samson
Schneider Downs & Co., Inc.
SM Energy Company
South Jersey Industries
Southwestern Energy Company
Statoil USA
Stone Energy Corp.
Talisman Energy Inc.
Talisman Energy USA Inc.
Tenaska
Texas Keystone Incorporated
Texon
Trans Energy, Inc.
Triana Energy, LLC
Turm Oil Inc.
Ultra Petroleum Corporation/Ultra Resources
Unit Corporation
Vavco, LLC
Whitmar Exploration Co.
Whittle Corporation
WPX Energy
XTO Energy/ExxonMobil
Zerkel Holdings, LLC
Zone Oil & Gas LLC