Simulation and Optimization of Trapping Processes for CO_2 Storage in Saline Aquifers

摘要

This paper describes the modelling of the main processes for CO_2 trapping in saline aquifers, namely solubility trapping, residual gas trapping and mineral trapping. Several important aspects of CO_2 storage are presented. It has been found that the total amount of CO_2 trapped as a soluble component, and as residual gas, can be enhanced by injecting brine above the CO_2 injector. An optimization technique is used to adjust the location and rate of the brine injector to maximize the total amount of CO_2 trapping. The security of the trapping process is then evaluated by taking into account the leakage of mobile CO_2 through the caprock. For long-term CO_2 storage, the conversion of CO_2 into minerals is found to depend on the pre-existing minerals in the aquifer that provide the necessary ions for the reactions to occur.