Rock/Fluid Interactions of Carbonated Brines in a Sandstone Reservoir: Pembina Cardium, Alberta, Canada

Abstract

Summary When CO2 is injected into petroleum reservoirs it forms carbonic acid in the brine phase and interacts with reservoir rock. Row tests were performed by continuously circulating CO2-saturated brines through Cardium formation cores. All the cores initially showed a large drop in permeability, after which permeability rose steadily but did not regain its initial value. Microscopic examination of the cores indicated that fines had been released and had migrated toward pore throats, reducing permeability. In addition, mineral alterations occurred, including the dissolution of calcite and siderite, which may account for the gradual rise in permeabilities noted in the experiments.