| The effects of carbon dioxide leakage on fractures, and water quality of potable aquifers during geological sequestration of CO2 |
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| 作者姓名： | Wei ZHANG Yilian LI Tianfu XU Wei QIANG Shangping XIAO |
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| 作者单位： | [1]School of Environment, China University of Geosciences. Wuhan 430074. China [2]Earth Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA |
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| 摘 要： | Since industrial revolution, the ＂greenhouse effect＂ is one of the most important global environmental issues. Of all the greenhouse gases, CO2 is responsible for about 64% of the enhanced ＂greenhouse effect＂, making it the target for mitigation, so reducing anthropogenic discharge of carbon dioxide attracts more and more attention. Geological sequestration of CO2 in deep saline aquifers is one of the most promising options. But because unknown fractures and faults may exist in the caprock layers which can prevent the leakage of CO2, CO2 will leak upward into upper potable aquifers, and lead to adverse impacts on the shallow potable aquifers. In order to assess the potential effect of CO2 leakage from underground storage reservoirs on fractures and water quality of potable aquifers, this study used the non-isothermal reactive geochemical transport code TOUGHREACT developed by Xu et al to establish a simplified 2-D model of CO2 underground sequestration system, which includes deep saline aquifers, caprock layers, and shallow potable aquifers, and study and analyze the changes of mineral and aqueous components. The simulation results indicated that the minerals of deep saline aquifers and fractures should be mainly composed of aluminosilicate and silicate minerals, which not only enhance the mass of CO2 sequestrated by mineral trapping, but also decrease the porosity and permeability of caprock layers and fractures to prevent and reduce CO2 leakage. The results from deep saline aquifers showed that the mass of carbon dioxide trapped by minerals and solution phases is limited, the rest remained as a supercritical phase, and so once the caprock aquifers have some unknown fractures, the free carbon dioxide phase may leak from CO2 geologic sequestration reservoirs by buoyancy.
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| 关 键 词： | 二氧化碳 数值模拟 含水层 重金属 孔隙度 水质 |
The effects of carbon dioxide leakage on fractures, and water quality of potable aquifers during geological sequestration of CO2 |
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| Wei ZHANG Yilian LI Tianfu XU Wei QIANG Shangping XIAO.The effects of carbon dioxide leakage on fractures, and water quality of potable aquifers during geological sequestration of CO2[J].Chinese Journal of Geochemistry,2006,25(B08):58-58. |
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| Abstract: | |
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| Keywords: | geological sequestration carbon dioxide numerical simulation potable aquifer heavy metal |
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