| 绿泥石对CO2-水-岩石相互作用的影响 |
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| 引用本文： | 杨国栋,李义连,马 鑫,董建兴.绿泥石对CO2-水-岩石相互作用的影响[J].地球科学,2014,39(4):462-472. |
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| 作者姓名： | 杨国栋 李义连 马 鑫 董建兴 |
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| 作者单位： | 1.中国地质大学环境学院，湖北武汉 430074 |
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| 基金项目： | 国家自然科学基金项目(No.41072180);国土资源部公益性行业科研专项(No.201211063);中澳CO2地质封存项目(No.CAGSII) |
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| 摘 要： | 为了解关键性矿物在“超临界CO2-水-岩石”系统中的地球化学作用，利用先进的数值模拟软件TOUGHREACT，结合我国鄂尔多斯盆地深部咸水含水层的基础地质条件，建立一维垂向模型，研究了盖层中绿泥石含量分别为3%、9%、15%时对CO2-水-岩石相互作用的影响.发现CO2进入盖层后，盖层的矿物成分和渗透率发生了较大变化.当绿泥石体积分数为3%时，盖层渗透率在5 000 a期间一直处于增大状态，不适合CO2封存；当绿泥石体积分数为9%和15%时，盖层渗透率呈现先增大后减小的趋势，产生自封闭现象，有利于CO2封存.结果表明，绿泥石的溶解为盖层中钙蒙脱石、铁白云石、片钠铝石、菱镁矿的沉淀提供了必要的Mg2+、Fe2+、AlO2-等离子.绿泥石含量越多，CO2矿化捕集量越大，盖层的自封闭效应越明显，其渗透率最大减少10%.本研究结果可为CO2地质封存的长期性和稳定性评价提供理论依据.
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| 关 键 词： | 绿泥石 盖层 CO2-水-岩石相互作用 自封闭 渗透率 数值模拟 环境地质 |
| 收稿时间： | 2013-08-19 |
Effect of Chlorite on CO2-Water-Rock Interaction |
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| Abstract: | In order to understand the geochemical processes of key minerals in the supercritical CO2 -water-rock system, we establish a one-dimensional vertical model to study the effect of chlorite contents in cap rock of 3%, 9% and 15% on CO2 -water-rock interaction by numerical simulation software of TOUGHREACT based on the basic geological conditions of deep saline aquifer in Ordos basin, China. It is found that the mineral composition and permeability of the caprock change greatly after CO2 broke into the caprock. It is not favorable for CO2 storage when chlorite volume fraction is 3% because of the increasing permeability in 5 000 years. The permeability of caprock increases first and then decreases when chlorite volume fraction is 9% and 15%, resulting in self-sealing which facilitates the sequestration of CO2. The results show that the dissolution of chlorite provides Mg2+, Fe2+ and AlO2- for precipitation of calcium montmorillonite, ankerite, dawsonite, and magnesite. The higher the chlorite content, the greater the amount of CO2 mineralization capture, and the more obvious the effect of caprock self-sealing with the maximum caprock permeability decrease of 10%. This study provides a theoretical basis for long-term geological storage of CO2 and its stability evaluation. |
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