A state of Wyoming report released on Thursday has concluded that natural gas drilling activity, including hydraulic fracturing (fracking), did not contaminate water wells in the town of Pavillion, which five years ago was the subject of controversial U.S. Environmental Protection Agency (EPA) tests tying the gas operations to water problems.
"Evidence does not indicate that hydraulic fracturing fluids have risen to shallow depths utilized by water-supply wells," according to the Department of Environmental Quality (DEQ) report. "Also, based on an evaluation of fracking history and methods used in the Pavillion gas field, it is unlikely that hydraulic fracturing has caused any impacts to the water-supply wells."
The report makes a series of recommendations for additional work, and it sets a public meeting for residents in Riverton, WY, on a still-to-be-determined day in early December. In addition, the DEQ plans to issue a "scope of work" to have supplemental groundwater investigations, including sampling/analysis of water-supply wells within the Pavillion gas field.
DEQ evaluated the data, conclusions and recommendations of an earlier report by the Wyoming Oil and Gas Conservation Commission (WOGCC) on wellbore integrity for oil/gas exploration and production wells within 1,320 feet of 14 domestic water wells previously identified for investigation.
WOGCC and DEQ retained third-party independent experts to assist their staff with the reviews, investigations, analyses and preparation of the reports, said a spokesperson for Gov. Matt Mead, who released the DEQ work.
Mead described the final report as "unbiased and scientifically supportable.”
Given the controversy surrounding the Pavillion gas field, it was important that baseline water quality be determined, along with proper water quality information and education, the governor's spokesperson said. In 2013, WOGCC started groundwater baseline sampling, analysis and monitoring requirements, including requiring oil/gas operators to test existing water sources before and after drilling.
In concluding that mostly naturally occurring seepage is taking place in the gas field, as opposed to leaking wells, the report said it is "undefined and difficult to quantify" the relative contributions of well leaks and naturally migrating gas supplies.
"Limited baseline water quality data predating development of the Pavillion gas field hinders reaching firm conclusions on causes and effects of reported water quality changes," the report said.
Nevertheless, residents and environmental groups that have been critical of the state's handling of the issue expressed skepticism to local news media.
"The data indicates that domestic water wells have been impacted by oil and gas extraction activities in the Pavillion field, and it's past time for both the state of Wyoming and Encana to publicly acknowledge the public health consequences and do something to make us whole," said John Fenton, chairman of Pavillion Area Concerned Citizens.
Mead's office said the state has spent $929,268 for the design, construction and installation of residential cistern systems and a water-loading station in Pavillion. To date, 31 cisterns for 28 landowners have been installed. For 11 landowners not participating in the cistern program, bottled water delivery has been extended through March 31.
Taste and odor complaints from residents in Pavillion began at least five years ago, prompting EPA involvement, to the consternation of Encana Corp.'s USA unit, the main gas field operator (see Shale Daily, Dec. 13, 2011). Eventually, through Mead's initiative, the state supplanted the federal agency in mid-2013, taking the lead in the investigation of the potential impact of natural gas production activities on drinking water in Pavillion (see Daily GPI, June 24, 2013).
Among the recommendations, DEQ and WOGCC are asked to continue discussions on evaluating potential groundwater contamination at pits and to evaluate consistent criteria for the closure of pits affecting groundwater. DEQ also recommends that U.S. EPA plug and abandon its two monitoring wells constructed in 2010 to eliminate any potential hazard to groundwater supplies and physical safety in the general area.
In characterizing the Pavillion field as a conventional, vertically drilled reservoir with unique characteristics, DEQ's report said evidence suggests that "upward gas seepage (or gas charging of shallow sands)" was happening naturally before gas well development. Further, "it is unlikely that hydraulic fracturing fluids have risen to shallower depths intercepted by water-supply wells."