Evaluation Method of CO2 Sequestration and Enhanced Oil Recovery in an Oil Reservoir, as Applied to the Changqing Oilfields, China

Injecting CO 2 into oil reservoirs was proven to have a great CO 2 sequestration capacity to reduce greenhouse gas emission and economic potentials via enhanced oil recovery (EOR). This paper proposes a CO 2 sequestration estimation method based on the material balance method, which considered the CO 2 displacement efficiency, CO 2 sweep efficiency, CO 2 dissolution, and some reservoir and fluid properties. The CO 2 EOR estimation method is also proposed and refers to the traditional petroleum engineering method. In the evaluation method of CO 2 sequestration and EOR potential, the sequestration coefficient and recovery factor are two important parameters. In this study, the stream tube simulation method is introduced to determine them. The evaluation method is applied to estimate the CO 2 sequestration capacity and EOR potential in the Changqing oilfield of China. The Changqing oilfield province lies in the Ordos Basin of western China. Published data indicate that the Changqing oilfield includes about 22 oilfields, and the majority of oil reservoirs are low-permeability reservoirs. The estimation results of CO 2 sequestration and EOR potential show that the Changqing oilfield is suitable for CO 2 sequestration and EOR and has great potential. Detailed evaluation of sequestration and EOR is worth further study.