Last year, contributor Joe Levine wrote a letter to Commissioner Joe Martens of the NYS Department of Environmental Conservation regarding the failure of the draft SGEIS to address the issue of fluid and gas migration related to horizontal hydro-fracking. The letter attached numerous primary source documents, but itself stands as a valuable and concise reference summary of the scientific evidence related to this topic. We are publishing it here as a three-part series, of which this is the second part. For Part I, click here.

Some of the most extensive studies on mapping of faults and fissures in NYS have been done by Robert Jacobi. This work has been endorsed and widely accepted by the scientific community (including the Society of Petroleum Engineers – SPE, NYSERTA, and the NYSDEC) and has not been challenged by any scientific organization, and is often referred to as the most extensive, documented mapping of NYS geology. It’s unacceptable that the DEC is not better informed; there is too much at stake.

The Jacobi report, Basement Faults and Seismicity in the Appalachian Basin of NYS; Jacobi 2009, states: “Seismic activity is most active along the myriad pattern of faults in NYS, …thus, it is not surprising that almost all of the seismic events in the Appalachian Basin portion of NYS can be correlated with the known and suspected faults. It appears that more faults are seismically active in NYS than previously supposed. It may be that most of the basement faults that extend to the surface rocks are seismically capable, even those that do not have historical seismicity ascribed to them. Further work will undoubtedly modify the specific locations of fault traces and their seismic capability. However, the conclusion is inescapable that a large number of faults do exist in NYS, and that several of them have been seismically active.” 1

Gas shales are often the origin of hydrocarbon stored in conventional reservoirs. These hydrocarbons have been expelled, migrating upward into a trap of reservoir quality rock below a sealing unit (often shale). In gas shale systems, the shale is all three: hydrocarbons are generated, stored and held in place. The preserved organic matter is “consumed” through biogenic or thermogenic processes to generate smaller chain hydrocarbons (gas or liquid). The remaining carbon that cannot be converted (dead carbon) and clay minerals form a storage mechanism through adsorption, which increases tremendously the potential storage volume. The relationship between temperature, pressure, available volume and the general attractiveness of methane (partial pressure) will define ultimate adsorbed storage capacity. Even after a great amount of generated gas is expelled out of the shale (as source rock), there can remain an enormous quantity as adsorbed gas. Gas will also reside in rock matrix pore space and fractures if there is a “seal” tokeep the gas in these spaces. 2

I will not elaborate on seismic activity in this commentbut do so for two reasons. One is that the Jacobi studies have so much to do with seismic activity, and second because of the recent reporting of earthquakes/seismic activity related to fracking (and/orinjection wells) in Ohio and before that in Arkansas, Texas, England and elsewhere. The OhioState geologist investigating the recent earthquake said that, “this could be avoided if more analysis (although costly) was performed so that wells intersecting with faults could be avoided” (Scientific American; Jan 3, 2012). This of course is likely impossible in NYS where the faults are so densely populated with literally a matrix of criss-crossing fractures (as described by Jacobi) that it would be quite difficult – if not impossible to avoid.

Also taken from Jacobi’s report: …Part of the multidisciplinary approach developed (by Jacobi andFountain 1996) was the identification of fracture intensification domains (FIDs; e.g., Jacobi and Xu,1998; Jacobi and Fountain, 2001, 2002). The FIDs are characterized by closely spaced fractures, the strike of which defines the trend of the FID. The closely spaced fractures are also commonly the master fractures, even though they may characteristically abut other fracture sets in regions outside the FID. Interbedded shales and thin sandstones in NYS, fractures within the FID that parallel the FID characteristically have a fracture frequency greater than 2/m, and commonly the frequency is an order of magnitude greater than in the region surrounding the FID. Jacobi goes on to say; An important observation is that these seismically active faults crisscross a large portion of NYS. The high number of faults means that most cultural facilities (e.g., waste disposal sites, bridges, pipelines) are not far from a potentially seismically active fault. For example, the West Valley faults extend south to the West Valley Demonstration Project, a high- and low-level radioactive waste storage site. Similarly, theAttica – Lockport Fault passes fairly close to the Darien Lakes theme park, where some of the highest amusement rides in the Northeast are located.

And one final example: in the Mohawk Valley region, the south end of the Hinckley Reservoir dam is adjacent to the Prospect Fault. Thus, it is vitally important to assess the maximum credible seismic eventthat can be expected along these faults. The maximum credible seismic event is extremely difficult to determine, partly because the historical recurrence rates of all earthquake magnitudes are relatively low in NYS (especially the moderate magnitude events) and because there may be a disconnect on Gutenberg – Richter curves between small events and maximum credible seismic events.

And most relevant with respect to migration from Jacobi; Certain sets of fracture intensification domains are marked by soil gas anomalies commonly less than 50m wide (Jacobi and Fountain, 1993, 1996; Fountain and Jacobi, 2000). In NYS, the background methane gas content in soil is on the order of 4 ppm, but over open fractures in NYS, the soil gas content increases to 40–1000+ ppm. (R.D. Jacobi/ Tectonophysics 353 (2002) 75–113 p79).

“The high concentration of gas in the faults is consistent with why drillers seek out the faults, because thisis where hydrocarbons exist in greatest concentrations because the faults provide both a pathway andcollection zone.” (Marc Durand) The Executive Summary also states “Hydraulic fracturing is engineered to target the prospective hydrocarbon-producing zone. The induced fractures create a pathway to the intended wellbore, but do not create a discharge mechanism or pathway beyond the fractured zone where none existed before. Accordingly, there is no likelihood of significant adverse impacts from migration of fracturing fluids. 3

This statement is not accurate and cannot be scientifically supported. Some of the released gas (with luck possibly most) will migrate up the wellbore as desired. But there is no doubt that some (also possibly most – if not lucky) will find other pathways. As per Marc Durand (below), fracking recovers only 20%of the gas in a reservoir until the well is capped due to productivity decline. The rest of the gas will migrate naturally – through the network of natural faults and fissures, including additional pathways opened up by fracking that were previously naturally sealed.

Click here for Part III, which reviews the work of Marc Durand and summarizes the argument.

1 JACOBI, ROBERT D., PhD, Geology, Columbia University. Basement Faults and Seismicity in the Appalachian Basin of New York State . November 2001, April 26, 2002.

2 MARTIN, JOHN P., et al. A Primer on New York’s Gas Shales http://offices.colgate.edu/bselleck/AppBasin/GasshaleMartin.pdf

3 JACOBI, ROBERT D., PhD, Geology, Columbia University.Basement Faults and Seismicity in the Appalachian Basin of New York State. November 2001, April 26, 2002.