摘要
苏南地区中浅层构造裂隙型地热资源丰富,是一种潜力巨大的清洁能源.本文从区域地质及物性资料入手,综合运用重力、磁法、电法、测温、测氡多种地球物理方法,通过多元物探信息融合,从热源、通道、储层、盖层四个方面开展地热地质条件研究.区域重力与面积性电测深资料揭示研究区属于隆、凹相间构造,表明中生代以来上地幔热动力作用强烈,具备寻找地热资源的有利构造条件.区内磁法异常平静、单调,不存在隐伏岩体等附加热源,地热主要来自地球内部自然增温.可控源音频大地电磁法资料揭示区内北东向与北西向断裂发育,其中北西向断裂具有张扭性质,规模及切割深度大,伴生浅表地温及放射性氡异常,是导水、导热的重要通道和控热构造.面积性电测深资料显示区内三叠系青龙组灰岩广泛分布,成为良好的裂隙-岩溶含水热储层,第四系松散层及白垩系浦口组厚度大,导热率低,有利于热储层蓄热增温,为理想的地热盖层.在对研究区源、通、储、盖四个要素进行综合研究的基础上确定了地热井位置RSQ1.经钻探验证,RSQ1井钻遇地层及构造情况与物探推断结果基本吻合,水量及水温参数均满足设计要求,充分说明综合地球物理方法在苏南地区中浅层构造裂隙型地热资源勘查中的有效性.
The mid-shallow tectonic fissured geothermal resource in Southern Jiangsu is very rich, and it’s also one kind of clean energy with great potential. Started with regional geology and physical property data, this paper comprehensively employed geophysical methods of gravity prospecting, magnetic prospecting, electrical prospecting, temperature measurement and radon measurement to carry out geothermal geological conditions survey from four aspects of heat source, channel, reservoir and cap rock. The regional gravity and areal electric sounding data reveal that the study area belongs to the uplift and concave structure, which indicates that the upper mantle has a strong thermal dynamic effect since Mesozoic era, and has favorable tectonic condition for searching for geothermal resource. The magnetic anomaly in this region is calm and monotonous, so there is no additional heat source such as concealed rock mass, the geotherm mainly comes from the natural increase of temperature inside the earth. Controlled source audio magnetometric data reveals the development of NW and NW faults in the region, in which NW faults have tensional property, large scale and cutting depth, associated with shallow surface geothermal temperature and radioactive radon anomalies, so it’s important channel for water and heat conduction and thermal control structure. Areal electric sounding data shows that the limestone of Triassic Qinglong formation is widely distributed in the area, making it a good fission-karst water-bearing thermal reservoir. Quaternary loose soils and Cretaceous Pukou formation are thick and have low thermal conductivity, which is conducive to heat storage and temperature increase of the thermal reservoir, making them an ideal geothermal cap. The location of geothermal well RSQ1 is determined based on the comprehensive study of the four elements of source, channel, reservoir and cap in the study area. The drilling result shows that the stratum structure and structure encountered in RSQ1 well are basically consistent with the geophysical inference results, and the parameters of water yield and water temperature meet the design requirement, which fully demonstrates the effectiveness of the comprehensive geophysical methods in southern Jiangsu mid-shallow tectonic fissured geothermal resource exploration.
作者
杨林
姜国庆
YANG Lin;JIANG Guo-qing(Geological Survey of Jiangsu Province,Nanjing 210018,China)
出处
《地球物理学进展》
CSCD
北大核心
2020年第6期2265-2275,共11页
Progress in Geophysics
基金
中国地质调查局苏南现代化建设示范区综合地质调查(12120115043201)资助。
关键词
地热资源
综合地球物理方法
苏南地区
地热异常
Geothermal resource
Comprehensive geophysical methods
Southern Jiangsu
Geothermal anomaly
