Friday, July 31, 2015
Driven in part by production from the Marcellus and other shale plays, natural gas has surpassed coal as the leading fuel source for U.S. electricity generation. And now a West Virginia University-led study suggests there’s more to come underneath the Marcellus. Results of the study provide evidence that the Utica play, which spans West Virginia, Pennsylvania, Kentucky, Ohio, and New York, is much larger than original estimates calculated, and its size and potential recoverable resources are comparable to the Marcellus, the largest shale oil and gas play in the U.S. and second-largest in the world.
Data from the “Utica Shale Play Book Study,” a two-year geological examination by the Appalachian Oil and Natural Gas Research Consortium (AONGRC), finds the majority of the Utica Shale lies beneath the Marcellus Shale. The interval between the two plays—the space between the Marcellus and the deeper Utica—ranges from 4000 feet in Ohio to more than 6500 feet in West Virginia. The drilling depth of the Utica ranges from less than 4000 feet in Ohio to more than 12,000 feet in West Virginia, which is more than two miles below the surface.
West Virginia University’s study shows that the Utica play contains technically recoverable resources of 782 Tcf of gas and 1960 MMbbl of oil. In a 2012 study, the U.S. Geological Survey estimated that technically recoverable sources in the Utica, the volume that can be extracted using existing technology, were 38 Tcf of gas and an additional 940 MMbbl of oil. A 2013 study by the U.S. Energy Information Administration reported that Marcellus Shale operators produced 2.86 Tcf of gas.
“The revised resource numbers are impressive, comparable to the numbers for the more established Marcellus Shale play, and a little surprising based on our Utica estimates of just a year ago which were lower,” said Douglas Patchen, director of AONGRC. “But this is why we continued work on the resource estimates after the project officially ended a year ago. The more wells that are drilled, the more the play area may expand, and another year of production from the wells enables researchers to make better estimates. Our research spanned basin-wide subsurface correlation and mapping of potential pay zones to macroscopic and microscopic examination of cores and thin sections of reservoirs to the nano-scale development of porosity in organic rich zones.”
In addition to estimates of oil and gas resources, the research team presented comprehensive data on the stratigraphy, petrology, reservoirs, and areal distribution of the play. Found was that the Utica play is actually neither Utica nor shale. Data point to an interbedded limestone and organic-rich shale interval in the underlying Point Pleasant Formation as the preferred drilling target. The most productive hydrocarbon source rocks tend to be the Point Pleasant and the upper and Logana members of the Lexington/Trenton Formation. The combination of a relatively shallow reservoir and the potential for liquids production make Utica an attractive play for producers. Original gas-in-place—the amount of hydrocarbons stored in the reservoir prior to production—is about 3192 Tcf and original oil-in-place is about 82,903 MMbbl. Finally, it is expected that given current technology the play-wide oil recovery factor will be about 3% and the gas recovery factor will be about 28% in the sweet spot areas.
Data from the “Utica Shale Play Book Study,” a two-year geological examination by the Appalachian Oil and Natural Gas Research Consortium (AONGRC), finds the majority of the Utica Shale lies beneath the Marcellus Shale. The interval between the two plays—the space between the Marcellus and the deeper Utica—ranges from 4000 feet in Ohio to more than 6500 feet in West Virginia. The drilling depth of the Utica ranges from less than 4000 feet in Ohio to more than 12,000 feet in West Virginia, which is more than two miles below the surface.
West Virginia University’s study shows that the Utica play contains technically recoverable resources of 782 Tcf of gas and 1960 MMbbl of oil. In a 2012 study, the U.S. Geological Survey estimated that technically recoverable sources in the Utica, the volume that can be extracted using existing technology, were 38 Tcf of gas and an additional 940 MMbbl of oil. A 2013 study by the U.S. Energy Information Administration reported that Marcellus Shale operators produced 2.86 Tcf of gas.
“The revised resource numbers are impressive, comparable to the numbers for the more established Marcellus Shale play, and a little surprising based on our Utica estimates of just a year ago which were lower,” said Douglas Patchen, director of AONGRC. “But this is why we continued work on the resource estimates after the project officially ended a year ago. The more wells that are drilled, the more the play area may expand, and another year of production from the wells enables researchers to make better estimates. Our research spanned basin-wide subsurface correlation and mapping of potential pay zones to macroscopic and microscopic examination of cores and thin sections of reservoirs to the nano-scale development of porosity in organic rich zones.”
In addition to estimates of oil and gas resources, the research team presented comprehensive data on the stratigraphy, petrology, reservoirs, and areal distribution of the play. Found was that the Utica play is actually neither Utica nor shale. Data point to an interbedded limestone and organic-rich shale interval in the underlying Point Pleasant Formation as the preferred drilling target. The most productive hydrocarbon source rocks tend to be the Point Pleasant and the upper and Logana members of the Lexington/Trenton Formation. The combination of a relatively shallow reservoir and the potential for liquids production make Utica an attractive play for producers. Original gas-in-place—the amount of hydrocarbons stored in the reservoir prior to production—is about 3192 Tcf and original oil-in-place is about 82,903 MMbbl. Finally, it is expected that given current technology the play-wide oil recovery factor will be about 3% and the gas recovery factor will be about 28% in the sweet spot areas.
