The amount of recoverable natural gas in the Marcellus and Utica shale formations in the Appalachian Basin is significantly greater than previously thought, according to a new estimate by the U.S. Geological Survey.
The USGS said in its latest assessment that the shale formations, both of which cover Western Pennsylvania, contain an estimated mean of 214 trillion cubic feet of “undiscovered, technically recoverable continuous resources of natural gas.”
The 2019 estimate represents a significant increase from previous USGS assessments of both shale 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.
“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.”
Advancements in drilling techniques and new geological knowledge account for the increased estimates, USGS said.
“Since our assessments in 2011 and 2012, industry has improved upon their development techniques for continuous resources like the shale gas in the Appalachian Basin,” said Walter Guidroz, program coordinator for the USGS Energy Resources Program. “That technological advancement, plus all of the geological information we’ve gained from the last several years of production, have allowed us to greatly expand our understanding of these formations.”
The natural gas is defined as continuous because, in both formations, it is spread throughout the assessed rock layers instead of being concentrated in discrete accumulations, USGS said. Production techniques like directional drilling and hydraulic fracturing, or fracking, are required to produce these resources.
The USGS assessments are for “undiscovered, technically recoverable resources,” meaning they have been estimated to exist based on geology and other data, and they can be produced using current standard industry practices and technology.
