带状热储地热田温度场特征及控热因素——以湖南省汝城县热水圩地热田为例  

Temperature field characteristics and thermal control factors of banded reservoirs geothermal field:an example of Reshui-town geothermal field,Hunan Province

作　　者：赵宝峰 汪启年[1] 官大维 陈同刚 方雯 ZHAO Baofeng;WANG Qinian;GUAN Dawei;CHEN Tonggang;FANG Wen(Geological Exploration Technology Institute of Anhui Province,Hefei 230041,Anhui,China)

机构地区：[1]安徽省勘查技术院,安徽合肥230041

出　　处：《地质通报》2022年第11期2035-2046,共12页Geological Bulletin of China

基　　金：国家重点研发计划项目课题《深部资源典型矿集区应用示范》(编号:2018YFC0603606)。

摘　　要：带状热储地热田是高品质地热资源的集中赋存区,热储构造分布极不均一,钻探风险高,温度场是认识热储分布的重要窗口。以湖南省温度最高、流量最大的汝城县热水圩地热田为例,通过温度场、水流量和岩心差异,识别了热田内不同热储构造区空间分布,探讨了控热因素的耦合关系,分析了形成高温大流量地热田的主控因素。研究结果表明,热储构造受走滑断裂破碎带控制,在平面上分异为6个区,主通道区、侧通道区和渗流通道区井温曲线形态依次为高幅蘑菇状、高幅瀑布状和高幅阶梯状,水温度依次降低,流量依次减小,水化学类型由HCO_(3)-Na型变为HCO_(3)-Ga-Na型,水流量等值线呈带状分布。温度在变质岩区迅速降低,显示出变质岩的侧向隔水隔热作用,垂向高温中心随埋深增大向东部迁移,热储裂隙内充填SiO 2与辉沸石,深部热水主要来自东部花岗岩区。热田发育在地形高差大、走滑断裂深切、岩石脆而致密的地区,受地形、断裂和岩性的共同控制,来自花岗岩地区的深循环热水,在浅部受到变质岩的侧向封堵,最终在多组断裂交会的山间洼陷集中排泄,形成高温大流量地热田。The banded reservoirs geothermal field is a storage areas of high-quality geothermal resources,and the temperature field is a window on the thermal storage structure which is extremely unevenly distributed.Taking Reshui-town geothermal field with the highest temperature and the largest flow in Hunan Province as an example,this paper identifies six different structural areas of reservoirs through the analysis of the temperature field,water flow and drilling cores in the geothermal field,and discusses the spatial coupling relationship of thermal control factors.The main conclusions are as follows:①The reservoir structure is controlled by the damage zone of strike-slip fracture and is divided into six areas on the plane;the main channel area,the side channel area and the seepage channel area have the well temperature curves shape of high-amplitude mushroom,high-amplitude waterfall and high-amplitude ladder;the water temperature and volume decreases accordingly;the hydrochemical type changes from HCO_(3)-Na type to HCO_(3)-Ga-Na type,and the water flow contours are distributed in bands.②The temperature drops rapidly in the area of metamorphic rocks,indicating the water insulation effect of metamorphic rocks in the sideways;the vertical high temperature center migrates to eastward with the increase of burial depth;the fillings of SiO 2 and stilbite in the thermal reservoir cracks,and the deep hot water mainly come from the eastern granite area.③The geothermal fields are developed in areas with large terrain height differences,deep strike-slip faults,brittle and compact rocks area,and are jointly controlled by topography,fractures and lithology.The deep circulating hot water from the granite area is blocked laterally by metamorphic rocks in the shallow part,and finally discharged centrally in the inter-mountain depression where multiple faults intersect,forming the geothermal field with high temperature and large flow.

关 键 词：带状热储 地热田 温度场 井温曲线 地热资源 

分 类 号：P314[天文地球—固体地球物理学]