Bioturbation and reservoir quality in the Cambro-Ordovician succession in southern Saskatchewan

In recent years, the Cambro-Ordovician Deadwood and Winnipeg Formations have become targets for geothermal energy production. Reservoir facies observed in core present abundant bioturbation which can affect permeability and fluid flow in media. To study the relationship between permeability, bioturbation, and fluid flow, we selected 6 facies with the best reservoir properties and different degrees of bioturbation. High-resolution permeability grids were obtained using a pulse-decay permeameter on slabbed core sections and the resulting data were used as input for finite difference numerical models of fluid flow for each sample. Our results demonstrate that bioturbation is associated with improved permeability in the Deadwood and Winnipeg Formations. Bioturbation intensity and grain size appear to be the main controls on the volumetric flux, with higher fluxes observed in sand-rich samples. Cryptic bioturbation is associated with good reservoir quality, while the best reservoir sections are associated with weakly defined bioturbation. The bioturbated Skolithos-bearing sandstones show the highest volumetric fluxes and are recognized as the best reservoir interval for geothermal energy.