Tracing environmental impacts associated with shale gas production with novel integration of isotopologue thermometry and noble gases

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With recent government green light for Lancashire fracking, concerns have arisen over the potential environmental impacts associated with drilling and shale gas production. One issue is whether fracking would introduce elevated hydrocarbon gas levels in drinking-water wells in the area of fracking. Several studies suggested that shale gas drilling could lead to fugitive gas contamination in a subset of drinking-water wells near drill sites, while others argue that methane is natural and unrelated to shale gas development. Much of this debate results from a lack of geochemical tracers that can constrain simultaneously the source, timing, and mechanism of hydrocarbon migration into shallow aquifers. The stable carbon (13C/12C) and hydrogen (D/H) isotopic composition of methane are traditional tools to identify the origin of methane in nature and trace fugitive gases from shale gas production. However, methane with different origins often yield overlapping isotopic compositions, which make such data inconclusive. Clumped methane has been validated as a thermometer, it is particularly useful to trace origin of methane gas, but the full potential and range of uses is yet to be developed. In contrast, noble gases have long been proven as a versatile tool in the investigation of origin and physical processes occurring in natural gas and hydrocarbon systems. This project will combine noble gases and clumped methane as a new set of tracers for identifying the origin and migration processes of stray gases from shale gas production.