Characterization, diagenesis, and geocellular modeling of Winnipegosis Formation pinnacle reefs in the Williston Basin, North Dakota

The Middle Devonian Winnipegosis Formation of the North Dakota Williston Basin contains pinnacle reef structures which have been targeted in the past for hydrocarbon production. These reefs have not been proven to hold economically important primary recoverable reserves, and are now being analyzed for potential CO2 EOR and storage applications.;During this study multiple sizes of Winnipegosis Formation pinnacle reef geocellular models were constructed utilizing data from North Dakota Winnipegosis pinnacle reefs wells, cores, and thin sections. These models were then simulated for CO2 injectivity.;Initial results show that Winnipegosis pinnacle reefs smaller than 1.5 miles in diameter are likely not feasible for CO2 EOR and storage applications. Results for pinnacle reef models 1.5 miles in diameter and greater may hold CO2 EOR recoverable reserves from 100,000-1,000,000 STB and may have the potential to store upwards of one million tons of CO 2.