CO2 storage in oil and gas reservoirs in western Canada: Effect of aquifers, potential for CO2-flood enhanced oil recovery and practical capacity

Abstract

This chapter explores that Prairie region in western Canada produces approximately one third of Canada's CO2 emissions. A comprehensive approach and associated methodology have been developed and applied for the evaluation of the theoretical, effective, and practical capacities for CO2 storage in these oil and gas reservoirs that take into account the presence and effect of underlying aquifers, reservoir heterogeneity, CO2 properties, and, in the case of oil pools, suitability for CO2-flood enhanced oil recovery (EOR). The flow strength and impact of the underlying aquifers can be established on the basis of the water-oil or water-gas ratio (WOR and WGR), together with the gas-oil ratio (GOR) in the case of oil reservoirs with a gas cap. Considering reservoir size, location, and depth, the practical CO2 storage capacity in western Canada is 3.2 Gt in 771 gas reservoirs and 560 Mt in 98 oil reservoirs, of which 81 are suitable for CO2 EOR.