A draft state report released Wednesday on a possible explanation why well water in a central Wyoming gas field smells foul and tastes bad points away from leaky gas wells as a source of the problem.
Testing showed no evidence gas wells in the Pavillion area are leaking produced gas into the ground or providing a route for deep gas to seep into aquifers tapped for household water, according to the draft report by the agency that regulates oil and gas development in Wyoming.
The release of the Wyoming Oil and Gas Conservation Commission report, which examined 50 gas wells within a quarter-mile of 15 water wells, opens a 30-day period for the public and others to weigh in on the draft findings.
Encana, the petroleum company that owns the Pavillion gas field, pointed to the latest findings as evidence their gas wells aren't to blame.
"The report confirms that the natural gas wells in the Pavillion Field were soundly constructed and provide no migration pathway into domestic water wells," Encana spokesman Doug Hock said in an emailed statement.
Local residents say their well water turned foul around the time gas drilling picked up in their area eight years ago. The draft report on the problem is the first of three planned by the commission and the Wyoming Department of Environmental Quality.
The U.S. Environmental Protection Agency, in a 2011 draft report, theorized gas development, including hydraulic fracturing, played a role. The report caused a nationwide stir as environmentalists cited it as evidence that upheld their long-held concern that fracking — the process of splitting oil- and gas-bearing rock with a high-pressure mix of water, fine sand and chemicals — can contaminate groundwater.
However, the EPA has yet to finalize its draft report or submit it for peer review. Last year, the EPA handed its Pavillion area investigation over to the state.
Part of a $1.5 million grant from Encana is funding the new state investigations. The first draft report examined the results of pressure testing of 41 wells by Encana between 2011 and 2013.
EPA spokesman Richard Mylott said his agency is reviewing the report. Gov. Matt Mead said he's pleased the report is out for public comment.
"Wyoming needs valid and reliable information regarding water quality in the area around Pavillion," Mead said in an emailed statement.
State officials initially planned to release the draft to the EPA and Encana for review, with public release only after the report was finalized. The draft report was released publicly Wednesday in response to requests by The Associated Press and the Powder River Basin Resource Council that cited Wyoming's open records law.
"We're just happy we've got it at the same time Encana has it," said Jill Morrison with the resource council, which has been working with Pavillion residents on their water problem. "It's complex, and we're going to be taking a really careful look at it with the assistance of an expert."
The report also found that potentially helpful information about how the water wells were developed, including how deeply they were drilled, is lacking. Seven of the 15 wells do not have water well permits on file with the State Engineer's Office, the report noted.
State officials plan to release two more reports by year's end on new sampling of Pavillion-area water wells and an investigation into whether old petroleum industry waste pits might have caused the problem.