Assessing Methane in Shallow Groundwater in Unconventional oil and Gas Play Areas, Eastern Kentucky

作者:Zhu Junfeng*; Parris Thomas M; Taylor Charles J; Webb Steven E; Davidson Bart; Smath Richard; Richardson Stephen D; Molofsky Lisa J; Kromann Jenna S; Smith Ann P
来源:Ground Water, 2018, 56(3): 413-424.
DOI:10.1111/gwat.12583

摘要

The expanding use of horizontal drilling and hydraulic fracturing technology to produce oil and gas from tight rock formations has increased public concern about potential impacts on the environment, especially on shallow drinking water aquifers. In eastern Kentucky, horizontal drilling and hydraulic fracturing have been used to develop the Berea Sandstone and the Rogersville Shale. To assess baseline groundwater chemistry and evaluate methane detected in groundwater overlying the Berea and Rogersville plays, we sampled 51 water wells and analyzed the samples for concentrations of major cations and anions, metals, dissolved methane, and other light hydrocarbon gases. In addition, the stable carbon and hydrogen isotopic composition of methane (delta C-13-CH4 and delta H-2-CH4) was analyzed for samples with methane concentration exceeding 1 mg/L. Our study indicates that methane is a relatively common constituent in shallow groundwater in eastern Kentucky, where methane was detected in 78% of the sampled wells (40 of 51 wells) with 51% of wells (26 of 51 wells) exhibiting methane concentrations above 1 mg/L The delta C-13-CH4 and delta H-2-CH4 ranged from -84.0 parts per thousand to -58.3 parts per thousand and from -246.5 parts per thousand to -146.0 parts per thousand, respectively. Isotopic analysis indicated that dissolved methane was primarily microbial in origin formed through CO2 reduction pathway. Results from this study provide a first assessment of methane in the shallow aquifers in the Berea and Rogersville play areas and can be used as a reference to evaluate potential impacts of future horizontal drilling and hydraulic fracturing activities on groundwater quality in the region.

  • 出版日期2018-6