综合物探方法在内蒙古敖汉旗林家地地热资源勘查中的应用试验

Application of comprehensive geophysical prospecting in the exploration of geothermalresources in the Linjiadi area, Aohan Banner, Inner Mongolia

在“碳达峰、碳中和”双碳目标背景下,如何科学、高效地进行地热资源的勘查开发是地热产业的关键问题。本文针对目前普遍关注的中深层地热资源勘查技术难题,以内蒙古敖汉旗林家地为研究区,开展了综合地球物理勘探方法的有效性试验研究。在区域地质条件和水文地质条件分析基础上,初步查明了敖汉旗林家地一带地温场特征和地下水化学特征;运用可控源音频大地电磁法(CSAMT)、微动测深和放射性氡气剖面测量多种方法组合,基本查明了研究区地层、岩浆岩及断裂构造的分布,推测了地热异常区控制因素及热水运移情况,并据此设定了勘探孔位,进行了960 m钻探验证。结果表明:综合运用可控源音频大地电磁法和微动测深等物探方法,并结合放射性氡气剖面测量进行辅助验证,对开展中深层地热资源勘查较为有效,可为其他地区地热资源勘查提供方法参考。

In the context of the goals of both peak carbon dioxide emissions and carbon neutrality,scientific and efficient exploration and exploitation of geothermal resources are criticalfor the geothermal industry.To address the commonly concernedtechnical challenges in the exploration of moderately deep geothermal resources,this study investigated the effectiveness of comprehensive geophysical prospecting in the exploration of geothermal resources inthe Linjiadi area,Aohan Banner,Inner Mongolia.Based on the analysis ofthe geological and hydrogeological conditions,this studypreliminarilyascertainedthe geothermal field characteristicsand the hydrochemicalcharacteristics of groundwater in the Linjiadi area.By comprehensively employingcontrolled source audio-frequency magnetotellurics(CSAMT),CSAMT;microtremor survey;radioactive radon survey;this study roughly determined the distribution of strata,magmatic rocks,and fault structures in the study area,inferring the factors controllinggeothermal anomaly areas and hot-water migration.Accordingly,exploration boreholes were arranged,allowing for drilling verificationwith a total length of 960 m.The results show that the comprehensiveapplication of CSAMT and microtremor survey,combined with radioactive radon survey for auxiliary verification,is effective in exploringmoderately deep geothermal resources.This study will provide a methodological reference for geothermal resource exploration in other areas.