GarCo consultant satisfied: No drilling-methane link
GLENWOOD SPRINGS — A geologist who has advised Garfield County regarding three studies on potential impacts of oil and gas development on groundwater south of Silt said Monday he doesn’t see a need for a fourth study unless new information surfaces to warrant it.
Consultant Geoffrey Thyne’s recommendation to Garfield commissioners comes after the third study concluded that methane showing up in groundwater appears to be naturally occurring, rather than from natural gas drilling in the area.
Thyne also praised the effort made by the county to date to study the matter.
“I’ve never seen an effort like this, not even close,” he said.
But Lisa Bracken, who lives south of Silt, believes an investigation needs to continue into a problem she considers much bigger than experts have acknowledged.
“It will eventually reveal itself for what it is,” she said.
The studies were prompted by the 2004 seep of gas from an Encana well into West Divide Creek. The Colorado Oil and Gas Conservation Commission concluded it resulted from problems with cementing of an Encana well, which allowed methane and benzene to reach a fault and migrate to the surface.
The commission fined Encana $371,200, which was used by Garfield County to pay for the first of its studies. Altogether they have cost more than $1 million.
Thyne earlier had feared that a leak was continuing despite repairs Encana had made to the well, and worried about a possible correlation between methane in water wells and drilling levels in the region.
But by 2012 falling methane and benzene levels in groundwater monitoring wells convinced him that the COGCC was right that the leak had been fixed and residual underground gas from the leak was dissipating. He’s likewise reassured by the latest study suggesting a natural explanation for methane in domestic water wells.
Thyne said measures imposed by the COGCC in recent years for drilling in the area, including more stringent well cementing requirements, have helped prevent repeat seep problems. He also praised the adoption of stricter COGCC rules statewide, including a requirement for testing of groundwater before and after drilling.
“It’s a huge step forward — long overdue,” he said of the testing requirement.
Bracken, who lives near the Encana seep area, takes issue with the conclusion of investigators that only a 400-foot-diameter surface area has been affected by a gas seep.
“That area was much, much more broad than was represented,” she said.
Thyne’s report to the county and related information can be found at http://www.garfield-county.com.