Numerical studies on the aquifer storage of CO2 containing N2

Abstract

Abstract The high cost of CO 2 capture is the one of most important barriers to large-scale CCS deployment. Impure CO 2 geological storage might be a cost-effective way to cut down the total cost of CCS by lowering the requirement of CO 2 capture or revenue-adding impurities. Primary cost analysis shows that injection of CO 2 containing some part N 2 might cut down the total CCS cost by lowing the capture requirement of CO 2 . Based on PVT characters of N 2 -CO 2 mixture, viscosity, relative permeability, capillary pressure model, hydraulic dispersion, geochemistry and COMSOL-Multiphysics software, the simulation tool is established and the migration process of N 2 -CO 2 mixture in sandstone core was studied by the tool. The numerical simulation have shown that preferential CO 2 solubility in brine compared to that of N 2 results in CO 2 being stripped off at the leading edge of the displacement front of fluid mixture containing N 2 that advances through the aqueous phase. The chromatographic partitioning process of CO 2 in gas phase can separate nitrogen and trap CO 2 in aquifer during preferential flow process, which caused by preferential solubility and mineral trapping during the CO 2 displacement process. The impact of N 2 will affect the migration of CO 2 plume, especially the migration front a lot underground