Isotopic and compositional characterization of natural gases in the Lower and Middle Triassic Montney, Halfway, and Doig formations, Alberta Basin

atural gases in the Montney, Doig, and Halfway formations are characterized by variations in the proportion of methane to higher alkanes, affecting calorific and commercial values. Stable isotope and compositional analyses suggest that wet gases in the central study area are produced via active thermogenic gas generation, with gases sourced in the Doig and Montney formations. Dry gases in shallow reservoirs near the Montney subcrop edge have a composition and isotopic signature characteristic of bacterial gas admixture. Deep Halfway and Doig gas pools on the western margin of the study area are extremely dry, having been generated at high source maturities. The non-hydrocarbon constituents...