A study that blamed natural gas drilling for water pollution in two states has spurred calls for stricter regulations to keep wells from leaking methane into aquifers.
The study backed the oil and gas industry in one respect: It discounted hydraulic fracturing, or fracking, as the source for harmful methane in water. Some environmentalists contend that by blasting rock with a mixture of water, chemicals and sand, producers can force the gas into drinking water near the surface.
The analysis, published in the peer-reviewed Proceedings of the National Academy of Sciences, found instead that leaks in the steel-and-cement casings surrounding the well bore were to blame. Imperfections in the seal allowed gas to escape before it reached the surface, making water undrinkable and in some cases explosive.
“The study appears to be attracting a lot of attention for the sometimes sleepy issue of well construction,” said Scott Anderson, a senior policy adviser at the Environmental Defense Fund, who has worked with gas driller Southwestern Energy Co. to develop well integrity guidelines. “This will help underscore the importance of recent and still-needed revisions in state regulations governing the drilling of wells.”
Fracking has pushed natural gas production to record levels in the U.S., lowering energy costs, supplanting higher-carbon coal in power generation and creating thousands of jobs. It has boosted industries like chemical makers that use it as both an ingredient for their products and a fuel. The process has been dogged by questions of its environmental risks, however, with groups like the Sierra Club pressing for stricter national rules to guard against water contamination.
The Bureau of Land Management, part of the Interior Department that regulates oil and gas production, three years ago said it planned to update rules for natural gas production on federal lands, given the increased development enabled by hydraulic fracturing, or fracking. The rules haven’t been issued.
Bob Abbey, the bureau’s director when it proposed the rules, said federal standards for well construction are key to limiting the risks of water pollution from drilling. The proposed rule will also focus on the release of information about the chemicals used in fracking, and the disposal of wastewater produced in the process.
“There are some good companies operating out there, and there are some not so good ones,” Abbey said. Federal rules can “provide assurance to the public that drilling can be done safely,” he said.
Jessica Kershaw, a spokesman for the Interior Department, said a draft of proposed rules has been sent to the White House for review. The new rules will “bring these requirements into the 21st century to keep pace with modern best practices,” she said in an e-mail.
As proposed, the BLM rule would require testing for leaks before hydraulic fracturing begins. Wells that penetrate underground drinking water sources also would have to record data on their cementing of wells to prevent leaks, and report the results to the government.
The draft could still be rewritten by the administration of President Barack Obama before the rule becomes final. Some producers objected to the proposal, saying tests would delay fracturing and tie up expensive rigs.
Another critical component, Abbey said, is having enough inspectors to ensure the standards are being followed.
States also have updated and toughened drilling rules, though advocates said more is required.
Pennsylvania tightened its regulations on well casings in February 2011 after concluding that wells drilled by Cabot Oil & Gas Corp. had leaked methane into nearby water wells.
The state also set standards for cement, used to seal the casing to keep gas from leaking. Reported cases of water supply contamination by stray gas from wells fell to two last year from 12 in 2010, according to the Pennsylvania Department of Environmental Protection.
Texas tightened requirements on well construction including casing in May 2013.
Wells must be tested to withstand the maximum pressure expected during fracking, and any failed test must be reported to the state, according to a statement by the Railroad Commission of Texas, the oil and gas regulator.
Colorado, meanwhile, requires the casing to extend from the surface to at least 50 feet below the groundwater aquifer at the site, according to an October 2011 report from the State Review of Oil & Natural Gas Environmental Regulations, a nonprofit that works with states on drilling and production standards.
The group has received funding from the U.S. Environmental Protection Agency, the U.S. Department of Energy and the American Petroleum Institute.
Wells must be pressure-tested in Colorado. The state imposed tighter casing standards in Garfield County, where water-well contamination has been reported, and for areas where gas is known to be under exceptionally high pressure, according to the State Review report.
Rob Jackson, a professor of earth sciences at Stanford University who helped write the study released Sept. 15 on leaks in Pennsylvania and Texas, said new rules are required to reduce pollution risks.
“We should be comparing states and adopting the most stringent standards we can,” he said in an interview.
A number of industry operators say that fracking poses little to no risk of fouling water supplies, although shoddy wells have the potential to do so. The more the distinction can be made, “it allows a rational conversation to take place,” said Paul Goodfellow, a vice president for Royal Dutch Shell Plc who helps oversee shale drilling in the U.S. and Canada.
“We’ve spent a fair amount of time talking about well construction,” said Goodfellow, who sits on the board of a non-profit that advocates for more environmentally friendly drilling practices. “Regulation is critical in this space, but even more important than good regulation is enforcement.”
While much of the debate over drilling has focused on fracking, Jackson said the general public doesn’t care in what way drilling posed risks to drinking water, only that it did.
“The differentiation between fracking and well integrity is important to the professionals, but to the public they don’t care about that distinction,” Jackson said. “Fracking and horizontal drilling has enabled the whole process, and they don’t care what step their water has been harmed by.”