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Evaluation of Methane Sources in Groundwater in Northeastern Pennsylvania
Author(s) -
Molofsky Lisa J.,
Connor John A.,
Wylie Albert S.,
Wagner Tom,
Farhat Shahla K.
Publication year - 2013
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/gwat.12056
Subject(s) - methane , groundwater , oil shale , extraction (chemistry) , geology , hydrogeology , natural gas , water well , bicarbonate , hydrocarbon , sodium bicarbonate , hydrology (agriculture) , sodium , unconventional oil , geochemistry , environmental science , chemistry , geotechnical engineering , organic chemistry , chromatography , paleontology
Testing of 1701 water wells in northeastern Pennsylvania shows that methane is ubiquitous in groundwater, with higher concentrations observed in valleys vs. upland areas and in association with calcium‐sodium‐bicarbonate, sodium‐bicarbonate, and sodium‐chloride rich waters—indicating that, on a regional scale, methane concentrations are best correlated to topographic and hydrogeologic features, rather than shale‐gas extraction. In addition, our assessment of isotopic and molecular analyses of hydrocarbon gases in the Dimock Township suggest that gases present in local water wells are most consistent with Middle and Upper Devonian gases sampled in the annular spaces of local gas wells, as opposed to Marcellus Production gas. Combined, these findings suggest that the methane concentrations in Susquehanna County water wells can be explained without the migration of Marcellus shale gas through fractures, an observation that has important implications for understanding the nature of risks associated with shale‐gas extraction.