DEP to review study linking shale drilling to methane contamination

http://citizensvoice.com/news/drilling/dep-to-review-study-linking-shale-drilling-to-methane-contamination-1.1144998#axzz1LwpBiOFT

By Laura Legere (Staff Writer)
Published: May 11, 2011

State environmental regulators are reviewing a study released Monday by Duke University researchers that found “systematic evidence” of a link between shale gas extraction and methane contamination of drinking water in Northeast Pennsylvania.

Department of Environmental Protection spokeswoman Katherine Gresh said in a statement that agency scientists are evaluating the study and “would like to see all of the authors’ backup data to review their methodology.”

The study found methane concentrations an average of 17 times higher in drinking water wells within a kilometer of active gas drilling than in water supplies farther away from the shale gas activity.

The study’s authors also published a white paper advocating regulatory changes, including tripling the radius from a proposed well site where natural gas drillers must perform pre-drill testing of water  supplies.

Gresh said the Duke researchers’ recommendations cover the kinds of subjects Gov. Tom Corbett’s Marcellus Shale Commission is evaluating. The commission is expected to present policy recommendations to the governor by mid-summer.

One of the study’s authors, Robert B. Jackson, said the data raise concerns about methane contamination that apply to shale drilling regions outside the study area in Northeastern Pennsylvania and Otsego County, N.Y.

The researchers found elevated methane in places residents suspected it, including in Dimock Township, where state regulators have documented nearly two dozen affected water supplies. But they also found elevated levels in unexpected places.

“We found other locations where, to my knowledge, the homeowners had no idea they had high methane concentrations,” Jackson said. “In fact our highest values weren’t in Dimock and they weren’t even in Susquehanna County. It is a hint that the problem is broader than people had thought.”

Former DEP Secretary John Hanger said it is clear that the geology in Susquehanna, Bradford and Tioga counties poses greater obstacles to drilling “safely and successfully” than the geology in other regions of the state.

State regulations enacted in February strengthened standards for casing and cementing gas wells to try to prevent cases of methane migrating up faulty well bores – the path the researchers said is the most likely cause for the elevated levels of methane they found in drinking water supplies in Susquehanna and Bradford counties. The rules also give the department “authority to require extra precautions where the geology is tricky,” which regulators used in Susquehanna County when he was secretary, he said.

“I would encourage the department to continue doing so,” Hanger said.

The commonwealth’s longtime stray gas inspector said he is “a little bit disappointed” with the study. Fred Baldassare, who now owns Echelon Applied Geoscience Consulting, said the authors fail to address the prevalence of naturally occurring thermogenic methane – gas that comes from deep underground, not from the breakdown of biological matter near the surface – in shallower geological layers between the surface and the Marcellus Shale.

“I’m not saying that gas well activity doesn’t cause gas migration, because of course it has,” said Baldassare, whose research is cited three times in the Duke paper. “We have documented cases of gas migration to private water supplies as a result of drilling activity.” But he added, “I think we have to take great care in trying to define what’s there naturally before we make judgements and conclusions about the origin of the gasses.”

In documented cases of stray gas caused by drilling in Susquehanna and Bradford counties, state regulators have found the gas migrating not from the Marcellus Shale but from shallower gas-bearing formations.

Baldassare said he is concerned the study might imply a migration straight from the Marcellus to aquifers, which he said he would “absolutely dispute.”

llegere@timesshamrock.com