The process of hydraulic fracturing is not intrinsically dangerous. A growing consensus among energy companies, state regulators, academics, and environmentalists is that the safety issue rests in well construction.
That is good news; it means that safe drilling is achievable through proper regulation and company due diligence. (Emphasis added.)
An important addition to this strengthening consensus came this month from scientists “often accused of anti-fracking bias” (as stated by The News & Observer, whose editors had previously expressed hope that their work, once published, would show that “perhaps fracking isn’t for North Carolina after all”).
A team of researchers from Duke University, The Ohio State University, Stanford University, Dartmouth College, and the University of Rochester analyzed 133 drinking water wells over the Marcellus Shale formation in Pennsylvania and 20 wells over the Barnett Shale formation in Texas, both places where there have been reports of methane in the water, which has caused some to suspect the culprit was hydraulic fracturing in local shale-gas extraction. Their findings were published in the Proceedings of the National Academy of Sciences.
The team “identified eight discrete clusters of fugitive gas contamination, seven in Pennsylvania and one in Texas.” They tested seven different hypotheses for the contamination, the sixth of which was “direct migration of gases upward through the overlying strata following horizontal drilling or hydraulic fracturing.”
In all eight clusters, they concluded that well failures were the cause, not fracking:
In general, our data suggest that where fugitive gas contamination occurs, well integrity problems are most likely associated with casing or cementing issues. In contrast, our data do not suggest that horizontal drilling or hydraulic fracturing has provided a conduit to connect deep Marcellus or Barnett Formation directly to surface aquifers. …
In our opinion, optimizing well integrity is a critical, feasible, and cost-effective way to reduce problems with drinking-water contamination and to alleviate public concerns accompanying shale-gas extraction.
Implications for Texas, site of the infamous flaming garden hose
A previous update and my Policy Report have discussed the Parker County, Texas, landowner in the video used in the movie “Gasland Part II” holding a garden hose spewing flames. The landowner, Steven Lipsky, had attached the hose deliberately to a gas vent over the well. Over a mile beneath the surface of Lipsky’s property are well lines operated by Range Resources, an oil and gas company.
In 2010 the U.S. Environmental Protection Agency issued an unprecedented “Substantial and Imminent Endangerment Order” that
natural gas drilling near the homes by Range Resources in Parker County, Texas, has caused or contributed to the contamination of at least two residential drinking water wells. Therefore, today, EPA has ordered the company to step in immediately to stop the contamination, provide drinking water and provide methane gas monitors to the homeowners.
In March 2011 state regulators with the Texas Railroad Commission concluded their investigation of wells in Parker County and determined that natural gas wells operated by Range Resources were “not causing or contributing to contamination of any Parker County domestic water wells.” Notably, the regulators found that
geochemical gas fingerprinting … demonstrated the gas in the domestic water wells came from the shallower Strawn gas field, which begins about 200 to 400 feet below the surface. The natural gas tested did not match the gas produced by Range from the much deeper Barnett Shale field, which is more than 5,000 feet below the surface in that area.
A year later, the EPA unilaterally removed its order. In 2014, the RRC returned to Parker County and retested wells but did not find sufficient evidence to conclude that Barnett Shale production activities were responsible for methane contamination in the aquifer. The RRC found on May 23, 2014, that “Contribution of natural gas to the aquifer by nearby Barnett Shale gas production is not indicated by the physical evidence.”
The RRC did, however, speculate that the presence of gas in the water may be due to “natural migration of gas from the shallow Strawn Formation, exacerbated by water well construction practices whereby some water wells have penetrated ‘red beds’ in the transition interval between the aquifer and the Strawn Formation.”
The newly published research found that the gas in the Barnett Shale area water wells they tested was similar in composition to Strawn-produced gases and therefore is “likely derived” from a Strawn source. Of their seven hypothesized scenarios, this Strawn-derived gas would in their assumption have entered the aquifer along the gas well annulus because of poor cementing.
That finding appears limited by the research question. The team does not appear to have even considered what the RRC found most likely: that some water wells — as opposed to nearby gas wells — might have penetrated the transition interval between the very shallow Strawn Formation and the aquifer.
Jon Sanders (@jonpsanders) is Director of Regulatory Studies for the John Locke Foundation.