Identifying the regional impact of deep thermogenic gas on aquifers in Alberta, Canada by comparing multilayered isoscape maps of domestic water wells and fugitive gases from energy wells

The origin and distribution of unwanted thermogenic gas in aquifers and domestic water wells in petroliferous basins are of continuing concern. Most published studies to date consider only a few water wells with little or no information on fugitive gases from nearby energy wells.   We mapped δ¹³C of  hydrocarbons in 1,124  domestic water wells and fugitive gases (many thousands) from energy wells of Alberta, Canada.  About 90% of the water wells that exsolve hydrocarbons produce methane derived locally by microbes. The δ13C of these biogenic methanes vary regionally and follows topography,  suggesting in situ generation of methane within a flowing aquifer perhaps following a Rayleigh constrained generation process. Some domestic water wells have free thermogenic butanes, propane and ethanes indicating the impact of thermogenic gas on the aquifer.  The δ¹³C of these thermogenic sourced gases impacting domestic water wells matches those of nearby energy wells indicating their failure as the ultimate source of thermogenic gas in domestic water wells.  The impacted water wells are geographically grouped. Our regional mapping of hydrocarbon gases in domestic water wells has identified specific, kilometre scale regions needing detailed hydrogeological and geochemical investigation.