Abstract: CO2 geological storage is one of effective measures for reducing emissions of greenhouse gases, and now CO2 disposal in deep saline aquifers becomes a feasible and most promising technology for CO2 storage. The previous studies show that the Songliao Basin is one of potential and promising storage sites. Based on the preliminary study of geological formation of the Songliao Basin, the first member of the Yaojia formation, the second and third members of the Qingshankou formation in the Sanzhao Depression are selected as the suitable aquifers for CO2 injection. Then a generalized two-dimensional model is set up to characterize the injection of CO2 into the Yaojia and Qingshankou formation, and to investigate the migration of CO2 in the aquifers. The results of model show that CO2 would migrate upwards and spread laterally over time after injection; and the phenomenon of convective mixing could occur obviously later, which could enhance the dissolution of CO2 process. The residual gas saturation and the ratio of horizontal to vertical permeability have the greatest effects on the results of model. Besides, the interbedded shale layers in the reservoir can enhance the dissolution of CO2. It’s suggested that the reservoirs with low-permeability intercalation could be allowed when the injectivity and storage capacity are guaranteed.

Key words: deep saline aquifers, CO2 geological storage, fluid migration, simulation, TOUGH2 code