In response to a study released in May by Duke University showing elevated levels of methane in water wells near active gas wells being drilled, Chesapeake Energy has released its own water testing data. One of the chief criticisms of the Duke study is that baseline measurements were not taken—that is, Duke did not test water wells before active gas drilling took place to eliminate the possibility that methane in those water wells was naturally occurring. Chesapeake has that data for wells close to its active drilling sites. The results are indeed interesting.
The Chesapeake data concerns West Virginia was provided via email to The State Journal:
Chesapeake Energy–funded laboratory tests find dissolved methane in about 11 percent of northern panhandle drinking-water wells before drilling for gas in the Marcellus shale ever begins.
Two wells of 1,312 tested in Brooke, Ohio, Marshall and Wetzel counties turned up with potentially dangerous levels of methane.
The state Department of Environmental Protection requires oil and gas operators to test the drinking-water well of any landowner or resident within a 1,000-foot radius of a proposed gas well who requests testing. If there are no requests, the operator has to sample a well or spring within 1,000 feet or, if none [if no water wells are within 1,000 feet], within 2,000 feet of the proposed well.
Chesapeake offers free water quality testing to anyone within a 2,500-foot radius, according to spokeswoman Maribeth Anderson.
Hired consultants collect the water samples and send them to third-party laboratories for analysis, Anderson said.
Of the 1,312 West Virginia water wells Chesapeake sampled, it detected methane in 11.1 percent: 11 percent in Brooke, 17 percent in Marshall, 8 percent in Ohio and 18 percent in Wetzel county. In Bradford County in northeast Pennsylvania, about 25 percent of wells have methane [before drilling begins], Anderson said.
The two West Virginia drinking-water wells that topped the 20 mg/L threshold were in Ohio and Marshall counties. One, Anderson said, was determined by chemical analysis to be from shallow coalbed methane; she did not explain the other.*
*Charleston The State Journal (Aug 7, 2011) – Chesapeake: 11 Percent of Water Wells Contain Methane Before Drilling