The U.S. Geological Survey has released its first oil, gas liquids and natural gas assessments for the unconventional Utica shale play that covers areas of Maryland, New York, Ohio, Pennsylvania, Virginia and West Virginia.
The Utica shale has a mean of 940 million barrels of undiscovered oil resources and a mean of 9 million barrels of natural gas liquids, USGS said. Oil ranged from 590 million barrels to 1.39 billion barrels, and gas liquids ranged from 4 to 16 million barrels, with a 95 percent probability the play holds the lesser amounts.
Utica also contains an estimated mean of 38 trillion cubic feet of undiscovered natural gas. Estimates ranged from 21 tcf to 61 tcf, with a 95 percent probability it holds the lesser amount.
The USGS assessment is an estimate of continuous oil, gas, and natural gas liquid accumulations in the Upper Ordovician Utica shale. It lies beneath the Marcellus shale, and both are part of the Appalachian Basin, which is the longest-producing petroleum province in the United States. The Marcellus shale, at 84 tcf of natural gas, is the largest unconventional gas basin USGS has assessed. This is followed closely by the Greater Green River Basin in southwestern Wyoming, which has 84 tcf of undiscovered natural gas.
Some shale rock formations, like the Utica and Marcellus, can be source rocks — those formations from which hydrocarbons, such as oil and gas, originate. Conventional oil and gas resources gradually migrate away from the source rock into other formations and traps, whereas continuous resources, such as shale oil and shale gas, remain trapped within the original source rock.
These new estimates are for technically recoverable oil and gas resources, which are those quantities of oil and gas producible using currently available technology and industry practices, regardless of economic or accessibility considerations.
USGS is the only provider of publicly available estimates of undiscovered technically recoverable oil and gas resources of onshore lands and offshore state waters. The USGS Utica shale assessment was undertaken as part of a nationwide project assessing domestic petroleum basins using standardized methodology and protocol.
“Understanding our domestic oil and gas resource potential is important, which is why we assess emerging plays like the Utica, as well as areas that have been in production for some time,” said Brenda Pierce, USGS energy resources program coordinator.
—Ray Tyson
