西藏谷露地热田地热地质特征  

Characteristics of Geothermal Geology of the Gulu Geothermal Field in Tibet

作　　者：高洪雷[1] 胡志华[1] 万汉平[1] 郝伟林[1] 张松[1] 梁晓[2] Gao Honglei;Hu Zhihua;Wan Hanping;Hao Weilin;Zhang Song;Liang Xiao(Beijing Research Institute of Uranium Geology,Beijing 100029,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China)

机构地区：[1]核工业北京地质研究院,北京100029 [2]中国地质大学地球科学与资源学院,北京100083

出　　处：《地球科学》2023年第3期1014-1029,共16页Earth Science

基　　金：中核集团集中研发项目(No:中核科发(2019)419号)。

摘　　要：西藏谷露地热田于2020年成功揭露到189.2℃的高温地热资源,研究谷露地热田地热地质特征,对西藏地热资源勘查开发和揭示高温地热系统成因机理都具有重要的科学与指导意义.本文以构造地质调查为基础,结合最新物探、钻探、水文资料,通过解析构造-水-热循环系统内在联系,总结构造控热规律,并建立了谷露地热田地热系统概念模型.谷露地热田内主要发育N-S向(F1、F3)、E-W向(F2、F4)和NE向3组断裂.大气降水与冰山融水沿盆地西侧九子拉-桑雄断裂下渗,经深循环加热以盆地西缘F1断裂为导热通道向上运移,由于受到南北两侧F2、F4断裂的阻隔作用,热水在F1和F3断裂组成的“Y”字型断裂系统内汇聚集中,形成热储,并在地表沿NE向和N-S向断裂构成的通道系统中运移排泄;盆地基底花岗岩之上覆盖的泉胶砾岩层对热储起到了良好的隔水保温作用;热田内第四系沉积很薄,热储主要赋存于基岩裂隙中,为基岩裂隙型热储.F1与F3构成的“Y”字型断裂系统是热储赋存的主要场所,谷露地热田地热资源勘查开发要以这两条断裂为重点勘查目标.The Gulu geothermal field successfully revealed high temperature thermal reservoir of 189.2℃ in 2020,therefore,studying geothermal geological characteristics of the Gulu geothermal field can be significant for guiding geothermal development and helpful for revealing the high temperature geothermal system mechanism.Based on the structural geological survey,combined with the latest geophysical,drilling,and hydrological data,this paper summarizes the structural thermal control laws of the Gulu geothermal field by analyzing the internal connection of the structure-water-thermal cycle system,and establishes a conceptual model of the geothermal system.The faults of the Gulu geothermal field can be divided into 3 groups:N-S trending(F1,F3),EW trending(F2,F4)and NE trending.Atmospheric precipitation and iceberg meltwater migrated deep along the Jiuzila-Sangxiong fault,and were heated by deep heat sources to form high-temperature geothermal fluids,and rose along the F1 fault at the edge of the basin.The hot water was blocked by the F2 and F4 faults near surface,converging into thermal reservoir,migrating and draining along the channel system which formed by the N-S and NE faults;The conglomerate cemented by sinter overlying the basement granite played a role in ensuring water and thermal insulation for thermal reservoir.The Quaternary sediments were very thin in geothermal field,and the thermal reservoir was mainly stored in the bedrock fissures.According to the results,the“Y”-shaped fault system formed by F1 and F3 faults is the main storage place for thermal reservoir,and these two faults can be regarded as the main target for deep geothermal exploration.

关 键 词：谷露 地热田 地热发电 概念模型 基岩裂隙型热储 

分 类 号：P548[天文地球—构造地质学]