Abstract: A method of sequestering carbon dioxide is provided, the method comprising injecting carbon dioxide into a saline formation below an oil reservoir. The carbon dioxide may be sequestered at a pressure above about 10 MPa. The carbon dioxide may be sequestered at a pressure below about 30 MPa. The carbon dioxide may be sequestered at a temperature above about 25° C. The carbon dioxide may be sequestered at a temperature below about 60° C. The saline formation and the oil reservoir may contact each other, thereby forming an oil-water contact (OWC) layer. The carbon dioxide to be sequestered may be injected greater than about 10 m below the OWC layer. The carbon dioxide may be a gas, a liquid, a supercritical fluid, or a mixture thereof, when the carbon dioxide is injected into the saline formation.