From the USGS:
The Marcellus Shale and Point Pleasant-Utica Shale formations of the Appalachian Basin contain an estimated mean of 214 trillion cubic feet of undiscovered, technically recoverable continuous resources of natural gas, according to new USGS assessments.
“Watching our estimates for the Marcellus rise from 2 trillion to 84 trillion to 97 trillion in under 20 years demonstrates the effects American ingenuity and new technology can have,” said USGS Director Jim Reilly. “Knowing where these resources are located and how much exists is crucial to ensuring our nation’s energy independence.”
The assessment unit map for the Marcellus Shale within the Appalachian Basin. Although it occupies similar areas as the Point Pleasant-Utica Shale, the Marcellus is much younger, having formed in the Devonian age. (Public domain.)
The Marcellus, Point Pleasant and Utica are extensive formations that cover parts of Kentucky, Maryland, New York, Ohio, Pennsylvania, Virginia and West Virginia.
This is a significant increase from the previous USGS assessments of both formations. In 2011, the USGS estimated a mean of 84 trillion cubic feet of natural gas in the Marcellus Shale, and in 2012 the USGS estimated about 38 trillion cubic feet of natural gas in the Utica Shale.
Significant amounts of natural gas have been produced from the Marcellus and Utica Shales since the previous USGS assessments. USGS assessments are for remaining resources and exclude known and produced oil and gas.Click here to read the whole announcement.