Methane in water wells unrelated to hydraulic fracturing

摘要

An extensive study backs what the locals already know - water wells in Pennsylvania have contained methane for hundreds of years. The rapid expansion of Marcellus shale gas extraction in the Appalachian basin of the northeastern US has prompted significant public concern regarding the potential for groundwater impacts due to hydraulic fracturing operations. This concern has been heightened by media coverage suggesting that hydraulic fracturing operations and gas extraction activities in northeastern Pennsylvania (Susquehanna County, in particular) have resulted in widespread occurrences of methane in shallow groundwater. However, the results of an extensive water well survey by GSI Environmental Inc. indicate that methane is commonly found in drinking water aquifers prior to proximate drilling activities in Susquehanna County. In addition, a review of relevant geologic and historic information, as well as isotopic analyses of dissolved gases, suggests that methane in Susquehanna County water wells is most likely associated with sources in the shallow subsurface or Upper Devonian gas-charged deposits that overlie the deeper Marcellus shale targeted for commercial development.