隐伏对流型地热资源勘查方法研究--以花亭湖风景区为例

Research on exploration methods of concealed convective geothermal resources:A case study of Huating Lake scenic spot

隐伏地热资源勘查一直是地热勘查的难点。为提高隐伏对流型地热资源勘查的“选区定位”精度,以安徽省太湖县花亭湖风景区为研究区,在充分了解地热田形成条件和主要特征的基础上,采用遥感解译、地热地质调查、可控源音频大地电磁测量和水化学分析等技术手段先后确定了重点区、地热靶区和验证孔位,最终发现水温为22℃,涌水量为780.4 m^(3)/d(降深S=20.62 m)的地下水资源,地下水化学特征与地热流体非常接近,含水段与可控源音频大地电磁测量(CSAMT)推断含水构造位置吻合;在此基础上,总结了研究区隐伏地热资源“选区定位”的工作流程,分析了勘查方法的应用效果,认为可控源音频大地电磁测量能够有效识别含水构造,系统的水化学分析是寻找地热资源线索的有效方法,寻找隐伏地热资源的关键是对控制地热形成的断裂体系的识别。

Exploration of concealed convective geothermal resources has always been a tricky issue in geothermal survey.In order to improve exploration precision of position selection in concealed convective geothermal resources,the authors in this research have taken Huating Lake scenic spot in Taihu County of Anhui Province as an example to determinate key areas,target areas and boring location through remote sensing interpretation,geothermal geological survey,CSAMT and hydrochemical analysis,based on the forming conditions and main features of regional geothermal fields.The groundwater with 22℃and 780.4m^(3)/d outflow(drawdown,S=20.62 m)was discovered,and its hydrochemical characteristics are similar to the geothermal fluid,with the consistent water-bearing structural location between actual aquifer and deduced aquifer by CSAMT.The exploration workflow for concealed convective geothermal resources exploration is summarized and the application effect of the exploration method is analyzed based on above research.The researchers in this paper conclude that water-bearing structure can be effectively identified by the CSAMT,and the effective way to determine geothermal resources is systematical hydrochemical analysis.Besides,it is essential to analyze and identify structure system of geothermal resources during exploration.