Hydraulic fracturing of shale formations to extract natural gas has no direct connection to groundwater contamination, according to a study by the Energy Institute of the University of Texas at Austin.
The study, released at a meeting of the American Association for the Advancement of Science in Vancouver, British Columbia, found that many problems ascribed to fracking actually have other causes, such as "casing failures or poor cement jobs."
University researchers also determined that many reports of contamination are the result of above-ground spills or other mishandling of wastewater from shale-gas drilling, rather than the fracking process.
"Our goal was to provide policymakers a foundation for developing sensible regulations that ensure responsible shale-gas development," said Charles "Chip" Groat, an Energy Institute associate director who led the study. "What we've tried to do is separate fact from fiction."
With the advent of intensive shale-gas drilling, fracking has become a controversial environmental issue and the subject of national studies, including one being done by the Environmental Protection Agency. The EPA study, which seeks to determine whether fracking is a significant threat to groundwater contamination and water quality in general, includes North Texas' Barnett Shale.
Groat disclosed during a Fort Worth speech in November that the study's preliminary findings showed no direct link between fracking and groundwater contamination.
Scott Anderson, a senior policy adviser for the Environmental Defense Fund, acknowledged in a statement on the group's website that the study "did not find any confirmed cases of drinking water contamination due to ... hydraulic fracturing." But "this does not mean such contamination is impossible or that hydraulic fracturing chemicals can't get loose in the environment in other ways (such as through spills of produced water)," he said. Produced water is wastewater that comes up a wellbore along with gas.
Fracking, widely employed in the Barnett Shale, blasts large volumes of water and sand, plus some chemicals, underground to fracture rock and allow natural gas and oil to flow into a wellbore.
The study also concluded that "natural gas found in water wells within some shale-gas areas ... can be traced to natural sources and probably was present before the onset of shale-gas operations."
The researchers examined reports of groundwater contamination attributed to fracking in the Barnett Shale, Marcellus Shale in Pennsylvania, and the Haynesville Shale in Louisiana and East Texas.
The EPA filed an emergency order against Fort Worth-based Range Resources in 2010, contending that two Range gas wells "caused or contributed" to contamination of two residential Parker County water wells with methane, a key component of natural gas. Range has denied the claims and is battling the EPA in federal courts.
Range has stressed that gas was found in water wells in the area before it began drilling there. But a couple that owns one well contends that improper casing and cementing of the Range wells led to the contamination, which the company also denies. A judge in Weatherford dismissed the couple's claim, saying they lacked legal jurisdiction because of a prior Texas Railroad Commission finding that Range's wells did not cause the contamination.