By Peggy Mackenzie
A new study has found evidence that poorly constructed wells and not frack chemicals are responsible for water contamination near natural gas wells, according to a report published in the Proceedings of the Natural Academy of Sciences. Instead, the study blames the contamination on problems in pipes and seals in natural gas wells.
“We found the evidence suggested that fracking was not to blame, that it was actually a well integrity issue,” said Ohio State University geochemist Thomas Darrah, lead author of the study. Those results, he said, are “good news” because that type of contamination problem is easier to fix.
The scientists reached their conclusions by chemically analyzing methane and other chemicals in the groundwater. That led them to link the contamination to particular wells, and then to discover what part of the drilling process was responsible. For example, they studied the precise proportions of methane, helium, neon and argon. Those proportions pointed to leaky pipes and seals, because the results would have been different if the contamination had come from fracking.
“I don’t think homeowners care what step in the process the water contamination comes,” said Rob Jackson, Stanford University environmental sciences professor and co-author of the study. “They just care that their lives have changed because drilling has moved next door.”
Since the fracking boom started in Pennsylvania in 2008, the state has identified 243 cases of private water supply contamination “impacted by oil and gas activities.” That is out of more than 20,000 wells drilled there.
The problem of leaky wells is one the gas industry has known about for decades. Another issue could be the hurry drillers are in during a boom has lead to poor quality wells, Jackson said.
Jackson and colleagues have been studying water contamination around natural gas wells for years and for this study they didn’t choose a random sample, but focused on areas that had more complaints of contamination. Even in those areas, it was only in a minority of sites that they could connect the contamination to the natural gas wells. In some cases, the contamination was natural and had no connection to gas wells, Jackson said.
Cindy Dunn, president of the environmental group PennFuture, said it isn’t surprising that the methane leaks problem is more due to poor pipes and cement seals, urging states to update regulations covering that topic.
Dave Spigelmyer, president of the Marcellus Shale Coalition of drillers, said his industry is working with state officials “to modernize and dramatically strengthen shale development-related regulations.”
The authors of the study, funded by National Science Foundation and Duke University, said their new means of fingerprinting natural gas uses concentrated inert noble gases such as helium and argon to determine whether gas in an aquifer has been there for decades or appeared only recently, flowing up through man-made wells bored into shale rock.
“The answer is not to stop drilling. The fix is better executions on the construction of the well and improving well integrity,” said Darrah.
Cornell University engineering professor Anthony Ingraffea, who wasn’t part of the study, praised it, but added that he’s worried because “it’s impossible to drill and cement a well that will never leak.”
“There’s still serious and significant harm from what’s coming before fracking and what’s coming after fracking,” Ingraffea said.