An assessment of tight oil resource potential in Upper Cretaceous Cardium Formation, Western Canada Sedimentary Basin

The Cardium Formation “halo oil” occurs either in the fringe of, or between, existing conventional discrete sandstone reservoirs. It is commonly associated with conventional oil and gas pools in stratigraphic traps. This paper uses a geological model-based simulation approach to assess Cardium “halo oil” resource potential. The geological model-based approach consists of a geological model, a resource model and a stochastic modeling procedure that extracts essential information regarding the richness and spatial characteristics of oil resources from various data sources using statistical methods. It integrates them with the geological and resource models, respectively, to estimate the resource potential. This approach predicts not only the resource potential, but also the resource spatial distribution and the exploration risk. These outcomes provide critical information for exploration decision-making. Cardium “halo-oil” assessment results indicate a mean total oil in-place (conventional and unconventional) of 4.6×109 m3 and a mean undiscovered “halo oil” in-place of 2.9×109 m3. Using current technology and economic constraints the undiscovered recoverable “halo oil” in this tight formation is 0.11×109 m3. This represents <4% of the remaining in-place oil resource, but it accounts for 38% of the total recoverable Cardium oil. A comparison with resource estimates obtained using a well-performance approach that is based on production data extrapolations from stimulated horizontal wells suggests that the mean recoverable estimate obtained using the two different approaches are similar, suggesting that the geological model-based approach provides a reliable oil resource potential estimate.