The effect of CO2 fluid on metals distribution in sandstones

• Main Authors: Yi-fei Chen, 陳怡妃
• Other Authors: Pei-shan Tsou
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/29446388344771541522

碩士 === 輔英科技大學 === 環境工程與科學系碩士班 === 100 === Geosequestration is one of mitigation methods for greenhouse effect. When CO2 were injected into the appropriate depth, target reservoirs were likely to have temperatures and pressures higher than the critical point for CO2. This study investigates into the CO2 fluid on water-rock interactions to explore the chemical form of metals in the sandstone under different temperature and pressure, and to investigate the possibilities and hazardous of metal into the groundwater. The results showed that the chemical form of metals in sandstones were significant different in the distribution. Ca, Mg, Mn, Fe and Ni mainly existed in the form of water soluble, exchangeable, carbonate, Fe-Mn oxide and organic phase. It indicated that these metals could change their forms by the change of pH, redox potential, organic matter content, or inorganic composition. Al and K mainly existed in the residual phase, and it is not easy to migrate into other phases. Ca, Mg, Mn, Ni, K and small amount Fe and Cu existed in the reaction solution of CO2-sandstone under different temperature and pressure conditions. The concentration of metals were highest at 40°C and 98 bar. In addition, the reaction solution of Fe, Mn, Cu and Ni content exceeds the drinking water source quality standards of ROC. Environmental impacts could be major if large volumes with mobilized toxic metals migrated into potable groundwater.