A 2D modeling study of different mechanisms of CO2 trapping in deep saline aquifers

The non-isothermal multiphase reactive geochemical transport code TOUGHREACT was used to establish a 2-D model for investigating trapping mechanisms of CO2 in deep saline aquifers. Quantitative assessments on different trapping mechanisms of CO2 in a saline aquifer have been obtained. The abundance of solution trapping is about 4.9 x 10(6), 3.4 x 10(6) and 2.9 x 10(6) kg after 10, 100 and 1000 years respectively. The abundance of mineral trapping is about 4.0 x 10(5), 6.8 x 10(5) and 5.9 x 10(6) kg after 10, 100 and 1000 years respectively. The abundance of gas trapping is about 2.5 x 10(7), 2.6 x 10(7) and 2.1 x10(7) kg after 10, 100 and 1000 years respectively. We can conclude that in addition to a fraction of the injected CO2 being trapped in mineral and solution phases, large amounts of CO2 injected into the deep underground storage reservoir are expected to remain as a supercritical phase.