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.