可控源音频大地电磁测深法在地热水找矿勘查中的应用

Application of controllable source audio magnetotelluric sounding in geothermal water prospecting and exploration

贵州省荔波县处于扬子准地台黔南台陷贵定南北向构造变形区的有利空间部位,该变形区发育一系列高温地热水资源,具有集中开发绿色清洁能源的优势。针对该区域热源异常区普遍埋藏深的特征,采用可控源音频大地电磁测深法对深部热源场和导热构造等进行了预测。结果表明:①研究区地表无明显的地热异常显示,但根据地质条件等综合认为该区域具有寻找深部热水的条件;②通过可控源音频大地电磁测深验证了该区域深埋的3条断裂构造,其低阻体的空间分布及延伸特征与耕者倒转背斜吻合,下部F 2上盘与其接触部位、低阻碎屑岩层下部存在的宽缓次低阻带,为研究区主要储水储热有利部位,是进一步勘查的重点靶区;③储水有利部位为埋深2000~2800 m的次低阻带,同时钻孔还应充分考虑F_(2)、F_(5)断裂在深部的空间展布情况。

Libo County in Guizhou Province is located in the favorable spatial part of the north-south tectonic deformation zone of Yangtze paraplatform platform collapse in south Guizhou and Guiding,which develops a series of high-temperature geothermal water resources and has the advantage of concentrated development of green and clean energy.In view of the characteristics of deep burial in the heat source anomaly area in this area,the deep heat source field and thermal conductivity structure were predicted by the controllable source audio magnetotelluric sounding method.The results showed that:①there was no obvious geothermal anomaly on the surface of the study area,but it was considered that the area had the conditions to find deep hot water according to the geological conditions.②The three deeply buried fault structures in this area were verified by controllable source audio magnetotelluric sounding,and the spatial distribution and extension characteristics of the low-resistance bodies were very consistent with the cultivator's inversion anticline,and the wide and gentle sub-low-resistance zone in the lower part of the lower F 2 wall and its contact part,and the lower part of the low-resistance clastic rock layer were the main favorable parts for water and heat storage in the study area,which were the key targets for further exploration.③The favorable part of water storage is the sub-low resistance zone with a buried depth of 2000~2800 m,and the spatial distribution of F_(2) and F_(5) faults in the deep part should be fully considered in the borehole.