Ichnology, sedimentology, stratigraphy, and trace fossil-permeability relationships in the Upper Cretaceous Medicine Hat Member, Medicine Hat gas field, southeast Alberta, Canada

The Upper Cretaceous Medicine Hat Member (Niobrara Formation) in western Canada contains abundant reserves of biogenic natural gas. In the Medicine Hat gas field area of southeast Alberta, nineteen cored intervals were examined and classified based on primary physical and biogenic sedimentary structures. Core analysis and stratigraphic mapping determined that the Medicine Hat Member strata consist of stacked, regionally extensive, lobate geobodies that prograde to the north. Employing spot-minipermeametry, the effect of biogenic rock fabrics on the reservoir characteristics was assessed. X-ray micro-computed tomography was conducted on four samples from a reservoir interval to visualize the geometry and distribution of burrow-associated heterogeneity. The results demonstrate that planiform bioturbate textures locally enhance the storage and transmission of natural gas in Medicine Hat reservoirs.