Officials in Three States Pin Water Woes on Gas Drilling
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The report, referred to as the Garfield County Hydrogeologic Study, has been met with cautious silence by the industry and by its regulators.
The Colorado Oil and Gas Conservation Commission, the state's regulatory body, would not respond to questions from ProPublica because it hasn't thoroughly analyzed the data behind the December report, said its director, David Neslin.
Neither the Colorado Oil and Gas Association nor Encana, the Canadian energy company that drills in the study area, would comment on the Garfield County report. Both referred questions to Anthony Gorody, a Houston-based geochemist who specializes in oil and gas issues and frequently is employed by the energy industry.
Gorody dismissed the report's conclusions as "junk science."
"This is so out of whack. There are a handful of wells that have problems. These are rare events," said Gorody, president of Universal Geosciences Consulting. "They are like plane crashes -- the extent tends to be fairly limited. I do not see any pervasive impact."
Most of the methane in the study area, Gorody said, came from decaying matter near the surface -- not from the deep gas produced by the energy industry. He criticized the report's methodology, saying the way that researchers linked the stray gas with the deep gas formations was speculative at best.
To Dimock resident Pat Farnelli, seen here pointing to the drilling rig in her backyard, the promise of making money off her family's land came at just the right time. But perhaps not at the right price. Now she spends more than $100 of her monthly food stamp allotment to buy plastic jugs of drinking water. (Abrahm Lustgarten/ProPublica)
Thyne, standing by his report, said researchers had traced the origin of the gas by conducting the equivalent of a forensic investigation, analyzing its isotopic signature, or molecular fingerprint. The molecular structure showed that most of it was thermogenic, meaning it matched the deeply buried deposit where gas was being drilled, called the Williams Fork Formation. A minority of the samples were difficult to identify by this method, so Thyne used another scientific process to study them. He is confident they, too, were thermogenic in origin.
In most cases, the study couldn't pinpoint the exact pathway the contaminants had used to travel a mile and a half up into the drinking water aquifer. So Thyne could only reason the possibilities.
The methane could be seeping into water wells through natural fractures, he said, or through leaks in the well casings or concrete, or from the well heads.
When a pipe extends 8,000 feet below the earth's surface, he said, "there are numerous potential leak points along the way. So is it leaking at 8,000 feet and coming up a well bore, a natural fault or fracture? Or is it leaking 500 feet from the surface? We don’t know."
The most plausible explanation, Thyne said, is that the same type of well casing and cementing issues that had proved problematic in Ohio were presenting problems in Colorado too.
"The thesis is that because of the way the wells are designed they could be a conduit," said Garfield County's Jordan, who commissioned the report.
Jordan worries that the methane leaks could be a sign of worse to come.
"We suspect the methane would be the most mobile constituent that would come out of the gas fields. Our concern is that it's a sort of sentinel, and there are going to be worse contaminants behind it," she said. "It's not just sitting down there as pure CH4 (methane). It's in a whole bath of hydrocarbons," she said, and some of those "can be problematic."