METHANE EMISSIONS FROM GROUNDWATER PRODUCTION OVER THE MARCELLUS PLAY

For over 25 years, the US EPA has reported annual greenhouse gas emissions and sinks to the United Nations according to the Framework Convention on Climate Change. The report includes all known anthropogenic sources of greenhouse gases that are monitored by various government agencies and reported in the Greenhouse Gas Reporting Program. Methane comprises a significant portion of the greenhouse gas emissions, second only in magnitude to carbon dioxide, and has 25 times the global warming potential of carbon dioxide.

The EPA uses a bottom up approach (site-level data, inventory-based approach) to measuring methane emissions. However, studies have shown that such methods may underestimate methane emissions from natural gas systems. A recent study over the southwestern area of the Marcellus Shale showed discrepancy in emissions from natural gas sources measured from ground-up methods when compared with measurements from the air, indicating that ground-up emissions estimates may omit a potential additional source of methane. Methane is common in shallow groundwater aquifers overlying the Marcellus Shale, yet methane emissions to the atmosphere from shallow groundwater extraction are not currently quantified. The diffusive nature of methane emissions from groundwater production has caused it to be overlooked when accounting for anthropogenic sources of methane.

The objective of this project is to determine methane flux to the atmosphere from shallow domestic groundwater production over the Marcellus Shale Play. The magnitude of flux is then compared to other currently measured methane fluxes to determine the relative impact of groundwater production on atmospheric methane budgets. Methane emissions from effusing groundwater contribute a small amount to atmospheric methane but are within an order of magnitude of some anthropogenic sources that are currently accounted for in methane emission estimates.