Faulty drilling practices, not hydraulic fracturing of natural gas wells deep beneath the surface, is the primary cause of water contamination in the Barnett Shale, a new academic study has found.
Scientists from Duke, Stanford and three other universities studied more than 130 water wells in North Texas and the Marcellus Shale in Pennsylvania and their findings suggest the methane gas found in water stems from faulty well casings and cement construction designed to protect groundwater during the drilling process.
It also states that the gas found in groundwater could be coming from other underground zones where fracking did not take place.
Published in the Proceedings of the the National Academy of Sciences, a peer-reviewed journal, and released Monday, the study is in direct contrast to some earlier examinations which found no evidence of contamination of drinking water from gas drilling in Texas or elsewhere.
Rob Jackson, one of the researchers, said he hopes that their findings will encourage the Texas Railroad Commission, which regulates the oil and gas industry, to re-examine wells in the Silverado subdivision in Parker County where higher-than-expected levels of methane gas have been found.
“We know for certain that some people’s water has been contaminated with methane from oil and gas activities and that it is possible that it will grow,” said Jackson, a professor of environmental and earth sciences at Stanford and Duke universities. “We saw homes go from clean to contaminated during the study and that is unique.
“I think it is reasonable to ask [the state] to retest some of these homes and to re-examine the production wells,” Jackson added. “I think people in Parker County need to know. They need to have it confirmed and, if it affected their drinking water, then they need a new source of water.”
Ramona Nye, a railroad commission spokeswoman, didn’t have any comment, saying that the agency’s staff is “reviewing the study, which will take a period of time to complete.”
But the oil and gas industry criticized the study, quoting a report released in May by the railroad commission that said while the amount of methane in Parker County water wells was increasing, it couldn’t be linked to nearby gas drilling activity.
The agency’s evaluation also indicated that the gas wells in the area were built in an effective manner that should not lead to any contamination.
“The gas wells were constructed right and had no integrity problems,” said Steve Everley, a spokesman for Energy In Depth, an industry education group. “The state has inspected them … you have to give more weight to the people who have actually inspected the wells.”
Well integrity crucial
In hydraulic fracturing, oil and gas producers pump millions of gallons of water underground to break up the shale rock and release the gas that is trapped there. The pipes that are used during the process are surrounded by concrete to protect the chemicals used, and the gas, from leaking out.
The horizontal drilling process was perfected in the Barnett Shale, an oil-and-natural gas bearing formation that lies beneath more than 5,000 square miles of North Texas. Since activity escalated in the early 2000s, more than 24,000 drilling permits have been issued, a recent study stated.
While fracking is credited with boosting the economy in North Texas and the rest of the country, critics worry about potential dangers. In Denton, for example, voters will go to the polls in November to decide if they want to ban the process within the city limits.
The newly released study won’t do much to calm anyone’s fears. Besides Duke and Stanford, scientists from Ohio State, Dartmouth and the University of Rochester also contributed to the report. They studied samples from seven clusters of wells in western Pennsylvania and one cluster in Texas, some that had already been contaminated. Sampling was done in 2012 and 2013.
Jackson and four other researchers analyzed the quantity and isotopes of noble gases such as helium and neon in the groundwater to try to determine if the fugitive gases are naturally occurring or caused by gas production. It’s the first time this kind of analysis has been done.
In four of the clusters, the team’s noble gas analysis shows methane from drill sites escaped into the water from shallower depths through faulty rings of cement covering a gas well’s shaft. In one cluster, it was linked to an underground well failure, the study said.
The study didn’t find that the injection of chemicals into the ground to free gas caused contamination.
“Our data do not suggest that horizontal drilling or hydraulic fracturing has provided a conduit to connect deep Marcellus or Barnett formations directly to surface aquifiers,” the study’s conclusion states. “Well integrity has been recognized for decades as an important factor in environmental stewardship for conventional oil and gas production.”
“Future work should evaluate whether the large volumes of water and high pressures required for horizontal drilling and hydraulic fracturing influence well integrity. In our opinion, optimizing well integrity is critical,” the study states.
Steve Lipsky, the Parker County resident whose flaming water sparked an emergency order by the U.S. Environmental Proteiction Agency in late 2010, said he was not surprised by the recent report. The contamination in his water was blamed on a well drilled by Fort Worth-based Range Resources.
“It is spreading and it’s getting worse,” Lipsky said. “Everyone knows you have to cement through a gas-bearing zone … Everyone’s gas is going up and it’s spreading and it’s not spreading by Mother Nature because it is spreading too high and too far.”
The railroad commission investigated and conducted tests of Lipsky’s well and at a 2011 hearing cleared Range. In 2012, the EPA withdrew its emergency order, although the company agreed to test 20 nearby water wells every three months for a year. Last year, the EPA’s inspector general determined that the agency had cause to act and should continue to assess contamination risks.
Range Resources has repeatedly denied any allegation that it contaminated Lipsky’s water and the company is suing Lipsky for defamation. A spokesman said they had not reviewed the latest report.
“Exhaustive studies have clearly demonstrated that no aspects of Range’s activities caused or contributed to the long-standing and well documented fact that gas is naturally occurring in the Trinity aquifer,” said Matt Pitzarella, a spokesman for Range Resources.
This report includes material from Bloomberg News.