Huge boost for Marcellus Shale reserves
The US Geological Survey estimates about 84 trillion cubic feet (cf) of natural gas and 3.4 billion barrels of natural gas liquids lies undiscovered in the Marcellus
The amount of recoverable natural gas from the Marcellus Shale play continues to climb after the US Geological Survey (USGS) boosted its reserve estimates for the unconventional play by 40 times.
The USGS says the Marcellus contains about 84 trillion cubic feet (cf) of undiscovered, technically recoverable natural gas and 3.4 billion barrels of undiscovered, technically recoverable natural gas liquids (NGLs). The estimates are significantly greater than the last USGS assessment, in 2002, which estimated a mean of about 2 trillion cf of gas and 100 million barrels of NGLs.
The increase in technically recoverable resources comes as a result of new geologic and engineering data, as well as technological developments in producing unconventional-gas resources.
Pennsylvania is already the oldest producing oil region of the US. Since the 1930s, almost every well drilled through the Marcellus found noticeable quantities of natural gas. But commercial gas production in the Marcellus began only in 2004.
In the wider Appalachian basin, the estimate of undiscovered gas ranges from 43 trillion cf to 144.1 trillion cf, and 1.6 billion to 6.2 billion barrels of liquids, all of it considered to be unconventional, the report notes. The Marcellus Shale assessment covered areas in Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia.
The USGS said it worked with the Pennsylvania Geological Survey, the West Virginia Geological and Economic Survey, the Ohio Geological Survey, and representatives from the oil and gas industry, and academia to develop an improved geologic understanding of the Marcellus as part of a nationwide project assessing domestic petroleum basins using standardised methodology.