Volume 35: CCUS Technologies for the Carbon Neutrality: Part III

Simulation study on the geological storage and transport of CO2 in the saline aquifer Guangda Ren, Yi Zhang

Abstract

With the rapid development of the global economy and the massive consumption of fossil energy, CO2 emissions are increasing year by year, leading to global warming and triggering a series of ecological and environmental problems. Carbon capture and storage (CCS) technology is one of the most promising CO2 emission reduction technologies. Subsurface storage of CO2 in deep saline aquifer has received much attention due to its potential huge storage volume and technical feasibility. The large-scale implementation of CO2 storage in saline aquifers is still confronted with complex reservoir structure, unclear spatial and temporal evolution of CO2, and difficult to predict spatial spreading, and there is an urgent need to clarify the carbon migration behavior and influencing factors in the reservoir. In this paper, a simulation study of CO2 storage in deep saline aquifer will be carried out in the Yaojia Formation of Sanzhao Depression in Songliao Basin. The 100-meter-deep sandstone stratum of the Yaojia Formation was selected for the study and divided into 10 lithologic layers, and the property parameters of each lithologic layer were assigned according to the actual situation. CO2 was injected at a rate of 10kg/s for a total simulation time of 250 years, including 10 years of injection, and the stationary observation is 240 years. The results show that the density of supercritical CO2 is slightly lower than that of water, and most of the CO2 will float upward and a small amount of CO2 will diffuse downward. After reaching the bottom of the cap layer, the CO2 plume will migrate laterally along the cap layer. At the beginning of injection, most of the CO2 will accumulate at the bottom of the cap, and a few will dissolve in the formation water. After injection stops, CO2 has a tendency to continue to accumulate and migrate laterally to the cap layer. Over time, convection phenomena favoring CO2 dissolution will occur.

Keywords CO2 geological sequestration, Deep saline aquifer, Numerical simulation