Gas probable culprit behind creek bubbles
Gas found seeping up along West Divide Creek south of Silt is probably coming from the same geological formation being drilled in the area, investigators have found.
Also, state regulators disclosed Monday that they were already working with the EnCana oil and gas company to rectify problems with two nearby wells when the seeping problem was discovered.
EnCana reported Monday at a meeting of Garfield County Commissioners that tests of area drinking wells so far show no detectable levels of benzene, toluene, xylene or ethylbenzene. But the company has committed to continue providing drinking water or filtering for residents and livestock in the area.
Colorado Oil and Gas Conservation Commission staff have found significant levels of benzene, which is a carcinogen, and non-dangerous amounts of toluene and xylene at the seep site.
EnCana on Monday placed some charcoal-activated booms in the seep area to try to absorb the contaminants from the water.
Gas conservation commission staff members collected gas from the half-mile-long seep site and sent it to a lab in Illinois for stable isotope analysis, a sort of fingerprinting of the gas, said Debbie Baldwin, the agency’s environmental supervisor. That analysis found a close chemical match between the seeping gas and Williams Fork formation gas tapped by four nearby gas wells.
“This is not biological gas seeping up,” said Baldwin, referring to gas created by decomposition of organic matter.
Nor does it appear to be coming from the Wasatch geological formation. Testing is revealing that the Wasatch formation contributes to low levels of methane gas in drinking water in the area, but that gas isn’t associated with drilling projects.
Jaime Adkins, area engineer for the gas conservation commission, said Monday the nearby Schwartz and Brown wells had not been cemented successfully, and the state had been working with EnCana on getting the situation rectified before the state agency first learned of the seepage April 1.
After drilling gas wells, crews inject cement between the well casing and the outside of the hole to seal off the gap between them. Despite the cementing problems with the two gas wells, investigators have yet to conclusively determine the source of the seepage.
“Connecting all the dots is what we’re working on and we may nor may not be successful in doing that,” Adkins said.
Baldwin said investigators can’t trace gas back to specific wells through isotope testing. If the leak can’t be traced, stopping it could be difficult, Adkins said.