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A major federal study of hydraulic fracturing in Pennsylvania was finalized last month. Conducted for the U.S. Department of Energy, the study’s preliminary findings have already been discussed in a prior issue of this newsletter as well as two separate reports.

What made this study so important to the ongoing research into horizontal drilling and hydraulic fracturing for oil and gas exploration and recovery was this: it was the first study to use tracers in the fluids injected down into the well during the fracturing process to see if they migrate back up. If they migrate back up, then they could possibly get into drinking water.

The fracturing fluids were injected over 8,000 feet (well over a mile) underground into the target Marcellus Shale formation. The researchers established monitoring zones to detect the tracer fluids in the Upper Devonian/Lower Mississippian gas field that is about 3,800 feet above the Marcellus (and still about half a mile beneath drinking water aquifers).

The preliminary results released in July 2013 were promising. The fluids had not been detected at the monitoring zones after a year; i.e., researchers had found "no evidence that chemicals from the natural gas drilling process moved up to contaminate drinking water aquifers."

The study also tested another concern for fluid (and fugitive gas) migration into aquifers — that maybe the fractures in the shale formation would extend into the overlying layers of solid rock, which if they extended far enough would provide alternative pathways for chemicals and stray gas to invade drinking water. They used seismic monitoring for microseismic events to determine how high the fractures went.

In final analysis, researchers found that the impact of fracturing did not extend far upward through overlying rock layers. A minority of microseismic events were located above the Tully Limestone formation 280 feet above the Marcellus Shale, but all were "at least 2,000 feet below" the Upper Devonian/Lower Mississippian and still about a mile ("more than 5,000 feet") below drinking water aquifers.

Also in final analysis, researchers found no evidence for fracking fluid migration or fugitive gas migration. As they wrote,

Conclusions of this study are: 1) the impact of hydraulic fracturing on the rock mass did not extend to the Upper Devonian/Lower Mississippian gas field; and 2) there has been no detectable migration of gas or aqueous fluids to the Upper Devonian/Lower Mississippian gas field during the monitored period after hydraulic fracturing.

This newsletter’s readers will recall that last month also saw the release of comprehensive (and long-awaited by fracking opponents, by the way) research by a team of scientists from several universities who found no evidence that the hydraulic fracturing process contaminated drinking water in Texas or Pennsylvania. That report underscored the growing consensus that fracking is an intrinsically safe process and that the key to safe recovery of oil and gas resources is proper well construction.

Law360 discussed the importance of both studies, whose findings were not only similar but also complementary:

What’s interesting is that while the university study examined whether fracking fluids could migrate to groundwater during the drilling process, the DOE study examined whether fracking fluids left behind after drilling could migrate to groundwater, according to McDermott Will & Emery LLP partner James Pardo, who frequently represents oil and gas companies.

"One was looking top-down, while the other was looking bottom-up, but they ultimately ended up in the same place," Pardo said.

The article also noted that the findings "put a major dent in lawsuits that claim groundwater contamination was caused by fracking." Actual groundwater contamination would therefore be either from actionable faulty well construction or an inactionable, localized, and ongoing act of nature.

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