Faulty fracking wells are to blame for drinking water contamination in Texas and Pennsylvania, according to new findings from researchers at five universities.
“People’s water has been harmed by drilling,” said Robert Jackson, a professor of environmental and earth sciences at Stanford University. “In Texas, we even saw two homes go from clean to contaminated after our sampling began.”
Construction problems with natural gas wells are responsible for the tainted water, the researchers found. That includes poor casing and failed cement jobs meant to seal the steel drilling pipe from surrounding earth and rocks and prevent water contamination.
The researchers said there was no evidence the water was contaminated by the process of hydraulic fracturing itself, known as fracking. Fracking is when high-pressure water and chemicals are pumped deep underground to break shale rock and release oil and natural gas.
That’s an important finding in the debate over fracking, which has unleashed an American energy boom but also allegations of pollution and health problems.
“The good news is that most of the issues we have identified can potentially be avoided by future improvements in well integrity,” said Thomas Darrah, an assistant professor of earth science at Ohio State University. He led the research while working as a research scientist at Duke University.
The researchers from Duke, Ohio State, Stanford, Dartmouth and the University of Rochester discovered clusters of methane contamination in drinking water wells along the Marcellus Shale in Pennsylvania and the Barnett Shale in north Texas, near Fort Worth.
Methane, the principal component in natural gas, is not known to be toxic, but it can be explosive and is a potent greenhouse gas.
The researchers found the Texas water contamination in southern Parker County. Their findings challenge the position of Texas oil and gas regulators that there is no evidence to connect reports of rising methane in several local wells to natural gas production.
Ramona Nye, spokeswoman for the Texas Railroad Commission, which oversees drilling, said in an email that she has no comment at this point.
“Our staff is currently reviewing the study, which will take a period of time to complete,” Nye said.
A spokesman for Fort Worth driller Range Resources said his company also has not had a chance to study the findings, released Monday by the Proceedings of the National Academy of Sciences. Range Resources has denied allegations that it was responsible for methane contamination in Parker County.
“The extensive testing conducted by Range and the Texas Railroad Commission prove that the two Range wells could not have been the source of the gas in any water wells, nor did any other aspects of our work,” said company spokesman Matt Pitzarella in an email.
The university researchers said they analyzed 20 drinking water wells overlying the Barnett Shale of Texas and found contamination in five of them. They said the contamination likely wasn’t from the Barnett Shale itself, but rather the shallower Strawn formation.
The Barnett Shale and Pennsylvania’s Marcellus Shale are at the center of a fracking boom that’s made the United States into the world’s largest natural gas producer.
The researchers used noble gas and hydrocarbon tracers to analyze more than 130 water wells in the two states over the past two years, focusing on areas of suspected contamination.
They said the “novel combination” of tracers let them distinguish between naturally occurring methane and contamination caused by fracking wells.
“This is the first study to provide a comprehensive analysis of noble gases and their isotopes in groundwater near shale gas wells,” said Ohio State’s Darrah.