A series of numerical simulations using a multiphase thermo-hydro-chemical (THC) numerical model is performed to analyze groundwater flow, carbon dioxide flow, heat transport, and hydrochemical reactive transport due to geologic storage of carbon dioxide in a deep saline sandstone aquifer and to evaluate impacts of its mineralogical compositions on trapping mechanisms and efficiency of injected carbon dioxide. The results of the numerical simulations show that the mineralogical compositions of the sandstone aquifer have significant impacts on behavior of injected carbon dioxide and thus its trapping mechanisms and efficiency. The mineral trapping of injected carbon dioxide takes places as the precipitation of the secondary carbonate minerals such as ankerite, dawsonite, siderite, and magnesite. Ankerite is the most contributive mineral for the mineral trapping of injected carbon dioxide. The amount of the precipitated secondary carbonate minerals and the efficiency of the mineral trapping increase significantly as the chlorite volume fraction increases. Therefore it may be concluded that both mineralogical compositions and hydrogeochemical reactions must be properly characterized and considered when more rigorous and reasonable predictions of long-term thermo-hydro-chemical responses of whole geologic systems to geologic storage of carbon dioxide and their storage stability are to be obtained using multiphase thermo-hydro-chemical numerical models.
