Impact of Injection Scenario on CO2 Leakage and CO2 Trapping Capacity in Homogeneous Reservoirs

Abstract The impact of different injection scenarios on the vertical CO2 leakage and on the capacity of CO2 storage in homogeneous reservoirs has been systematically investigated by comparing the total vertical CO2 plume migration distance, the amount of free CO2 and the capacities of capillary and solubility trapping obtained. A 3D homogeneous reservoir simulation model has been developed to simulate a CO2 plume behavior for three different injection scenarios (water alternating CO2 (WACO2) injection, periodic injection and standard continuous CO2 injection). The injection period was 20 years and the total amount of injected CO2 was 20 Mton, for all injection scenarios. Then, after the end of the injection period, a storage period of 200 years was simulated. We then compared the CO2 leakage and the amount of free, dissolved and trapped CO2 between these three injection scenarios. The results show that, after 200 years CO2 storage period, injection scenario significantly affects the vertical CO2 leakage and the CO2 trapping capacities in homogeneous reservoirs. Firstly, our results show that the standard continuous CO2 injection and periodic injection scenarios lead to increase the CO2 mobility and vertical CO2 leakage. In addition, the simulation results show that the amount of CO2 trapped (by both residual and solubility trapping) in the standard continuous CO2 injection scenario is less than that trapped in the other injection scenarios. Thus, we conclude that injection scenario has an important effect on the CO2 sequestration processes.