Identifying the Source of Methane in Groundwater in a ‘virgin’ Area with Regards to Shale Gas Exploitation: A Multi-isotope Approach

Abstract

The Upper Ordovician Utica Shale located in the St. Lawrence Lowlands (Quebec, Canada) represents a promising reservoir of unconventional gas, which is still ‘virgin’ with respect to fracking due to a de facto moratorium. A project was initiated in order to evaluate the vulnerability of shallow groundwater with respect to potential future activities carried out at depth. The geochemical aspect of the project, relying on isotopes of various compounds from shallow groundwater and rock samples, will help establish baseline gas concentrations in the aquifer, evaluating whether gas concentrations and isotopic ratios vary over time, and identifying the source(s) of methane.