The U.S. Geological Survey (USGS) on Thursday sharply raised its assessments for the Marcellus and Utica shale formations, estimating they hold a mean of 214 Tcf of undiscovered, technically recoverable natural gas resources -- with the Utica now topping the Marcellus.
The revised figures also include estimates for the Point Pleasant formation, a deeper horizon below the Utica often targeted by unconventional producers.
The new assessment is a significant increase from the last time USGS updated the figures. In 2011, the Marcellus was estimated to contain 84 Tcf and in 2012 it estimated that the Utica contained 38 Tcf.
However, Utica-Point Pleasant development has increased since the last assessment, which was conducted at a time when commercial production was only beginning to materialize in Ohio.
In a turnabout, USGS now estimates that there is more natural gas in the Utica than the Marcellus. The latest update estimates that the Utica-Point Pleasant contains 117.2 Tcf, compared to an estimated 96.5 Tcf in the Marcellus.
“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 USGS’ Walter Guidroz, who oversees the 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.”
Natural gas in the formations is classified as continuous, USGS said, because it’s spread throughout the assessed rock layers instead of being concentrated in certain areas. Directional drilling and hydraulic fracturing are required to produce the resources, it added.
USGS assessments are for remaining resources and do not include known and produced oil and gas.
The assessment also estimated that the Marcellus contains 1.5 billion bbl of natural gas liquids (NGL). The Utica-Point Pleasant is now thought to contain an estimated 1.8 billion bbl of oil and 985 million bbl of NGLs.
The formations are massive and underlie parts of Kentucky, Maryland, New York, Ohio, Pennsylvania, Virginia and West Virginia. The Utica also extends into Canada, but the areas assessed include only the states. The formations have been most fruitful in Ohio, Pennsylvania and West Virginia, where producers have pushed natural gas production to record levels.
Appalachian production has skyrocketed over the last decade from about 2 Bcf/d in 2010 to current levels of more than 32 Bcf/d.
Late last year, USGS said the Permian Basin’s Wolfcamp and Bone Spring formations in the Delaware sub-basin contain an estimated mean of 46.3 billion bbl of oil, 281 Tcf and 20 billion bbl of NGLs of undiscovered, technically recoverable resources. USGS said it was the largest continuous assessment ever. More recently, the agency sharply reduced its estimates of natural gas hydrate resources in Alaska’s North Slope.