This post continues my series on unconventional wells that have been omitted from the Pennsylvania Department of Environmental Protection’s Act 13 reporting, with a look at wells in the Medina Group. In Northwestern Pennsylvania the Medina Group consists of three lower Silurian-aged members: Grimsby Sandstone, Cabot Head Shale, and Whirlpool Sandstone.
Figure 36 of Oil and Gas Developments in Pennsylvania in 1987 provides summarized records of 391 well completions that penetrated formations of Middle Devonian age or older (i.e., to the Marcellus Formation or lower). The majority of these wells were categorized as producing from the Medina Group. Details on the depths to and thicknesses of each of these three members, together with the depths of the producing interval, were provided for approximately 350 Medina Group completions. Using these data it is simple (if tedious) to calculate whether or not the Cabot Head Shale was completed. If my math is correct, 198 out of 350 Medina Group wells were completed in the Cabot Head Shale.
The Appalachian Basin Tight Gas Reservoirs Project, a three-year project sponsored by the U.S. Department of Energy and undertaken by the West Virginia Geological and Economic Survey and the Pennsylvania Geological and Topographic Survey, reported on 10,906 Medina completions in Pennsylvania through approximately 2007. Assuming the ratio of Cabot Head Shale to Medina Group wells from 1987 holds for other time periods, this would suggest approximately 6,170 Cabot Head Shale completions.
This is significant, because any well completed in the Cabot Head Shale meets Act 13′s definition of an unconventional well, and thus, is required to pay unconventional impact fees. Assuming these wells were all vertical, that would be a fee of at least $8,000 for 2011, or a total of more than $49 million in impact fees due under Act 13. And yet, none of these wells were included in the Pennsylvania Department of Environmental Protection’s reports to the Pennsylvania Public Utility Commission as required by Act 13.
As startling as this oversight is, the above estimate likely understates the number of Medina Group wells liable for unconventional impact fees. First, I have been overly conservative in my calculations — only including wells that explicitly completed the Cabot Head Shale. In many cases the wells reported in 1987 were completed to within a foot or so of the Cabot Head Shale. Because the Medina is generally more than 2,000 feet below the surface, any hydraulic fracturing of the Grimsby Sandstone or the Whirlpool Sandstone will grow vertically, and therefore, penetrate and produce from the Cabot Head Shale. In that case, the number of unconventional wells may include every Medina Group well ever completed. If so, the impact fees due under Act 13 would grow to more than $87 million.
Second, I have only reported on completed wells, but Act 13 requires that impact fees be paid on all spud unconventional wells. A well is spud the moment drilling begins. As a consequence, the number of spud wells is likely to be meaningfully higher than the number of completed wells, but so far I have not found a data source that would allow me to reliably estimate the ratio of spud wells to completed wells for the Medina Group during this time period. Whatever this ratio turns out to be, it simply adds to the magnitude of the reporting failures by the Pennsylvania Department of Environmental Protection.
Third, to estimate the total population of Medina Group wells I used the well database generated by the Appalachian Basin Tight Gas Reservoirs Project. But it is likely that this is actually not the population of Medina wells, but only a sample of them. To the extent that more than 10,906 Medina wells were spud in Pennsylvania in the Cabot Head Shale, then my estimate of the impact fees due is too low.
In sum, my analysis suggests the operators of Medina Group wells collectively owe a minimum of $49 million to $87 million in unconventional well impact fees under Act 13, and the total could be much higher. And yet none of these wells has been reported as required by the Act.