Pam Kasey, writing for the State Journal, has described the recent estimate for the Marcellus technically recovered reserves of natural gas. Here is her description:
West Virginia’s Marcellus shale resource is estimated at 8.9 trillion cubic feet in the June 25 release of the U.S. Energy Information Administration’s Annual Energy Outlook. In July 2011, the EIA published an estimate of the remaining technically recoverable resource, or TRR, in the Marcellus of 410 trillion cubic feet. TRR includes proved reserves — volumes expected to be produced under existing technological and economic conditions — and unproven resource that it is believed existing technology could extract.
That 410 tcf came into question in August, when the United States Geological Survey refreshed its estimate of the Marcellus TRR at a mean value of 84 tcf, with a range of 43 to 144 tcf. Then, in its January early look at the Annual Energy Outlook 2012 reference case, based on the USGS figures but also extrapolating from more recent production data from Pennsylvania and West Virginia, the EIA’s new estimate of the TRR came in right at the top of the USGS range: 141 tcf.
The EIA provided details of that estimate in the full AEO2012. The EIA uses almost all of the USGS’s assumptions; the difference is that the EIA’s “estimated ultimate recovery” in the core of the Marcellus is higher: 1.95 billion cubic feet per well, compared with the USGS’s 1.15 bcf.
The EIA is specific in its estimates of the TRR for various portions of the Marcellus and for each of the eight states it encompasses. Of the 141 tcf it estimates as technically recoverable, more than 60 percent is in Pennsylvania and almost 30 percent is in New York — totaling more than 90 percent. About 8.9 tcf, or a little over 6 percent, is in West Virginia.
For scale, the state’s total gas production in 2010, not only Marcellus but all gas, was 265 billion cubic feet, according to the EIA. If 8.9 tcf of Marcellus were recoverable, it would represent more than 33 years’ worth of the state’s total 2010 production.
Background information to the estimates shows that the Marcellus region is 99 percent to 100 percent “untested” — that is, there’s no data. So even while being quite specific, the EIA was cautious about its estimates. “The estimation of Marcellus shale gas resources is highly uncertain, given both the short production history of current producing wells and the concentration of most producing wells in two small areas, Northeast Pennsylvania and Southwest Pennsylvania /Northern West Virginia,” the AEO2012 reads.