摘要
广西贺州地热资源丰富,所蕴含的地热能潜力巨大,极具开发前景和研究价值,但该地区地热资源存在补给来源、循环演化过程及成因机制不清的问题。本研究通过地热地质调查、地球物理、地球化学和环境同位素等方法探究贺州杨梅冲地热水的热储特征、补给来源、循环深度和成因模式,初步建立地热资源温度、组分、深度、磁性等参数与地质认识一致的地质-地球物理模型和隆起山地断裂对流型地热概念模型。结果显示,杨梅冲地热田属带状热储,姑婆山断层是杨梅冲地热田主要导水、控热构造。杨梅冲地热田地热流体水化学类型为HCO_(3)-Na型。氢氧同位素显示区内地热水的补给来源于降水入渗。降雨在水力和热力的驱动下沿着断裂带和岩石孔隙循环交替水热对流,形成了杨梅冲断裂对流地热模型。研究结果为广西杨梅冲地热资源的勘查和合理利用提供理论依据。
Hezhou in Guangxi is rich in geothermal resources with great development prospects and research value.However,there are problems to be addressed in terms of supply sources,cyclic evolution processes,and genesis mechanisms of geothermal resources in this region.Through geothermal geological surveys and analyses of geophysics,geochemistry,and environmental isotopes,this study has explored thermal storage characteristics,supply sources,circulation depths,and genetic models of the geothermal fields in Yangmeichong,Hezhou.A geological geophysical model and a convective geothermal model of uplift mountain faults have been preliminarily established,whose geological parameters such as temperature,composition,depth,and magnetism of geothermal resources are consistent with the understanding of geology.The thermal reservoir of geothermal fields in Yangmeichong is belt shaped and composed of the Yanshanian granite fracture zone.The Guposhan Fault(F1)is the main water conducting and heat controlling structure in the geothermal fields in Yangmeichong.The source of geothermal heat flow in the geothermal fields is the heat from the upper mantle and deep crust(mantle heat flow),as well as the heat generated by the decay of radioactive elements in the shallow crust(crust heat flow),providing a heat source for the formation of deep circulating groundwater.Temperatures and geothermal gradients gradually increase from the western boundary(F1-1)to the eastern boundary(F1)and from the northern boundary to the southern boundary of the geothermal fields in Yangmeichong.In the vertical direction,geothermal gradients increase with the increase of depths.Temperatures within the depth range of 800-1,200 m are 53.5-73.0℃,and the geothermal gradient is 4.88℃/100 m.The deep thermal storage temperatures of the Yangmeichong geothermal fields have been measured by both silicon dioxide geothermal temperature scale and potassium magnesium geothermal temperature scale,and temperatures are 92.24℃and 87.22℃,respectively.Accordingly,the depths of underground thermal mineral water circulation are 3,292 m and 3,069 m,respectively.The hydrochemical type of geothermal fluid in the geothermal fields in Yangmeichong is HCO_(3)-Na.Due to the leaching effect of deep groundwater on granite bodies,the contents of silicic acid and sodium ions in underground hot water are relatively high.The isotopic detection results indicate that the supply of geothermal water in the area comes from precipitation infiltration,and the tritium content of geothermal water is less than 2 TU.It is speculated that geothermal water in Yangmeichong was formed by atmospheric precipitation before 1960.The geothermal energy in Yangmeichong is a fault convection geothermal model.Geothermal water is directly supplied by atmospheric precipitation with fault zones and rock pores as water channels,and it flows deep by both hydraulic and thermal forces.After alternating water thermal convection,geothermal water is formed.Subsequently,the convection of geothermal water took place along the fault of Gupo mountain from deep to shallow and from north to south,which formed the fault convective geothermal model in Yangmeichong.The research results provide a theoretical basis for the exploration and rational utilization of geothermal resources in Yangmeichong,Guangxi.
作者
王新伟
张漓黎
李善民
WANG Xinwei;ZHANG Lili;Li Shanmin(China Nonferrous Metals(Guilin)Geology and Mining Co.,Ltd.,Guilin,Guangxi 541000,China;Guangxi Institute of Regional Geological Survey,Guilin,Guangxi 541000,China)
出处
《中国岩溶》
CAS
CSCD
北大核心
2024年第4期876-888,921,共14页
Carsologica Sinica
基金
2021年广西重点研发计划项目“漓江流域废弃采石场生态修复技术集成与示范”(桂科AB21220049)
国家重点研发计划课题“漓江流域喀斯特自然景观修复与植被生态功能提升关键技术研发及试验示范”(2019YFC0507503)。
关键词
杨梅冲地热田
流体地球化学
热储循环深度
地热概念模型
the geothermal fields in Yangmeichong
fluid geochemistry
depth of geothermal reservoir circulation
geothermal conceptual model
