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Abstract: The high cost of CO2 capture is the one of most important barriers to large-scale CCS deployment. Impure CO2 geological storage might be a cost-effective way to cut down the total cost of CCS by lowering the requirement of CO2 capture or revenue-adding impurities. Primary cost analysis shows that injection of CO2 containing some part N2 might cut down the total CCS cost by lowing the capture requirement of CO2. Based on PVT characters of N2-CO2 mixture, viscosity, relative permeability, capillary pressure model, hydraulic dispersion, geochemistry and COMSOL-Multiphysics software, the simulation tool is established and the migration process of N2-CO2 mixture in sandstone core was studied by the tool. The numerical simulation have shown that preferential CO2 solubility in brine compared to that of N2 results in CO2 being stripped off at the leading edge of the displacement front of fluid mixture containing N2 that advances through the aqueous phase. The chromatographic partitioning process of CO2 in gas phase can separate nitrogen and trap CO2 in aquifer during preferential flow process, which caused by preferential solubility and mineral trapping during the CO2 displacement process. The impact of N2 will affect the migration of CO2 plume, especially the migration front a lot underground [Copyright &y& Elsevier]

Abstract: Carbon dioxide capture and geological storage (CCS) is regarded as an effective option to reduce CO2 emissions from the use of fossil fuels. CCS is particularly important to China due to its large and rapidly rising emissions and high dependence on fossil fuel, and large remaining coal reserves. This paper presents the key results of the authors’ study to evaluate o pportunities for the deployment of CCS technologies within China. It focuses on the data, methodology, and results of basin-scale CO2 sto rage capacity and CO2 point emission estimation in China. There is a total estimated theoretical CO2 geological storage capacity of 3088 gigat ons in China’s onshore and offshore basins, including a storage capacity of 3066 gigatons for deep saline formations accounting for 99% of total geological storage resource. China also has an annual emission about 3.9 billion tons of CO2 from large point sources in 2007. In view of initial site-source matching analysis, He huai Basin, Bohai Bay Basin, Subei Basin and Sichuan Basin have the best potential for CCS deployment. There is significant potential for CCS technologies to deliver deep, sustained and cost-effective emissions reductions for China over the course of this century [Copyright &y& Elsevier]