Reservoir Simulation of CO2Sequestration in Brine Formation

Abstract

Considering the long-term and slow processes of CO2sequestration in brine formation, it is hard to systematically investigate the underlying mechanisms of CO2sequestration in a saline aquifer with bench-scale experiments. In this work, simulation research of CO2sequestration in a real saline aquifer was proposed and conducted to investigate the effects of CO2injection on the formation and to reveal the mechanisms of CO2sequestration. To be specific, the simulation of CO2sequestration was carried out with both a homogeneous model and a heterogeneous model. The former model aimed to investigate the effect of CO2injection rate on the reservoir conditions and the formation properties. The latter one focused on unveiling the impacts of heterogeneity of formation properties and geological structure, two critical inlierent properties of the real saline aquifer, on CO2distribution and trapping. The results show that the distribution of pH was affected by the distance to the injector, geological structure, and heterogeneity of permeability. The lowest pH, which was controlled by the maximum formation pressure and corresponding solubility of CO2, can be found in the location of the CO2injector. The porosity changes caused by the reaction with solid minerals in both two models were relatively small after 30 years of CO2injection. Meanwhile, the maximum formation pressure was undisputedly located at the CO2injector. Then, the formation pressure will gradually decrease with an increase in the distance to the injector satisfying a power function.