Cite this article: Jean, J.S., Hsiang, H.I., Li, Z., Wong, C.L., Yang, H.J., Yang, K.M., Wang, C.L., Lin, H.W. and Kuo, C.C. (2016). Influence of Supercritical CO2 on the Mobility and Desorption of Trace Elements from CO2 Storage Rock Sandstone and Caprock Shale in a Potential CO2 Sequestration Site in Taiwan.
Aerosol Air Qual. Res.
16: 1730-1741. https://doi.org/10.4209/aaqr.2015.12.0665
Release of metals found in distilled water in absence and presence of scCO2 assessed.
Dissolution of Fe, Sr, Ba seen in water from storage rock sandstone or caprock shale.
In the presence of scCO2, the dissolution of these metals was drastically reduced.
Permanent sequestration of scCO2 into carbonate minerals was suggested.
Dissolution of Sr-bearing and precipitation of Ba-bearing mineral also indicated.
Excess carbon dioxide emission was considered as the most important cause of increased trend of global warming. Significant amounts of research were devoted to the reduction of CO2 emission and CO2 sequestration. Sequestration of CO2 in empty oil reservoirs was considered as one of the most promising options. However, the effects of metal release and mobility as a result of CO2 injection were not studied in detail, particularly under super-critical CO2 (scCO2) conditions. In this study, the release of selected metals immersed in distilled water for varying amounts of time in the absence and presence of scCO2 was assessed in simulated conditions at 90°C and 24 MPa. Significant increases in dissolution of Fe, Sr, and Ba by 3, 8, and 24 times were found when the storage rock sandstone or caprock shale was immersed in DI water for different time period. However, in the presence of scCO2, the dissolution of these metals was reduced by 80% for Fe, suggesting permanent sequestration of scCO2 into carbonate minerals. The trend in changes of pore water chemistry in the sandstone and shale after being immersed in DI water showed dissolution of Sr-bearing mineral and precipitation of Ba-bearing mineral.
Keywords: CO2 storage; Metal release; Sequestration; Mobility; Supercritical CO2