Zhou Shutao, Sun Qiang, Zhang He, Meng He, Gao Qian, Zhou Yang
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi, 710054, China.
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi, 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation,Xi'an, Shaanxi 710054, China; Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources, Xi'an, Shaanxi, China.
Sci Total Environ. 2023 Nov 1;897:165455. doi: 10.1016/j.scitotenv.2023.165455. Epub 2023 Jul 11.
In the process of developing hot dry rock (HDR) through enhanced geothermal systems (EGS), it is necessary to inject circulating water to complete thermal energy extraction. However, the injected water will react with the high-temperature rock and produce mineral dissolution, which can destroy the artificial reservoir and affect the development of geothermal energy. To explore the influence of temperature on the solution composition and mineral dissolution after water-rock reaction, this study conducted water-rock interaction experiments on gabbro and granite at different heat treatment temperatures. Subsequently, the changes of solution composition and mineral dissolution with temperature after the reaction were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and XRD. The results demonstrated that Si, Na, Ca, K, Al, and Mg did not enter the aqueous solution at the same dissolution rate. Si was the primary solute in the solution, mainly resulting from the dissolution of quartz, and the dissolution rates of metallic elements were lower. In the granite-water interaction system, metallic elements such as Na, K, Ca, and Al showed a tendency to enter the solution at low temperatures, i.e., 150-180 °C, and the dissolution rate of Si reached its peak when the water was close to the supercritical state. With the increase in temperature, the dissolution rates of Si and metallic elements showed an initial increasing trend followed by a decrease. When water is in the subcritical to the supercritical state, abrupt fluctuations in the physical properties of water can strongly affect the dissolution of minerals or rocks. The results of this study provide insights into rock corrosion fatigue and mineral scaling in EGS water environment.
在通过增强型地热系统（EGS）开发干热岩（HDR）的过程中，需要注入循环水以完成热能提取。然而，注入的水会与高温岩石发生反应并产生矿物溶解，这可能会破坏人工储层并影响地热能的开发。为了探究温度对水岩反应后溶液成分和矿物溶解的影响，本研究对不同热处理温度下的辉长岩和花岗岩进行了水岩相互作用实验。随后，通过电感耦合等离子体质谱仪（ICP-MS）和X射线衍射仪（XRD）分析了反应后溶液成分和矿物溶解随温度的变化。结果表明，硅、钠、钙、钾、铝和镁并非以相同的溶解速率进入水溶液。硅是溶液中的主要溶质，主要源于石英的溶解，而金属元素的溶解速率较低。在花岗岩-水相互作用体系中，钠、钾、钙和铝等金属元素在低温（即150-180°C）时呈现进入溶液的趋势，当水接近超临界状态时，硅的溶解速率达到峰值。随着温度升高，硅和金属元素的溶解速率呈现先增加后降低的趋势。当水处于亚临界至超临界状态时，水的物理性质突然波动会强烈影响矿物或岩石的溶解。本研究结果为EGS水环境中的岩石腐蚀疲劳和矿物结垢提供了见解。
