Experimental study of CO2 storage in water-flooded oilfields

Abstract CO 2 is the main source of greenhouse emission, and the environment problem caused by greenhouse effect has drawn worldwide attention. In most oilfields in China, a method of waterflooding is usually used to enhance oil recovery, which is favorable to carry out CO 2 injection study. The CO 2 injection in the water-flooded oilfields can not only store CO 2 , but also enhance the oil recovery. In this article, the core-flooding tests with refined oil were conducted to investigate CO 2 displacement characteristic in water-saturated formation under different injection rate and water-flooded oil reservoir under different formation pressure and oil saturation, then the CO 2 storage capacity was calculated. The testing result shows that the displacement efficiency increases with the rise of the CO 2 injection rate, and the CO 2 injection can enhance the oil recovery about 15% OOIP under the experimental condition. When injecting CO 2 after the waterflooding, the CO 2 storage capacity increases as the rise of the formation pressure. The core-flooding tests also indicate that when the initial oil saturation of reservoir prior CO 2 injection is higher, the oil recovery will be higher when injecting the same pore volume (PV) of CO 2 , and the CO 2 storage capacity will be larger.