广东龙门地区岩溶热储特征及地热系统成因OACSTPCD
Characteristics of karstic reservoir and mechanism of geothermal system in Longmen area of Guangdong Province,China
中国广东省地热资源丰富,岩溶热储分布广泛,极具勘探开发潜力.研究岩溶型地热系统成因对广东省乃至中国南方岩溶型地热资源的勘探开发利用具指导意义.采用地质调查、钻井测量和水文地球化学等方法,多视角系统性地研究广东龙门地区岩溶型地热田特征及其形成机理.结果表明,龙门地区岩溶热储层主要赋存在龙门和永汉等断拗陷盆地的下石炭统石磴子组(C1sh)和上泥盆统天子岭组(D3t)碳酸盐岩层中,以岩溶溶洞裂隙热水为主,埋藏浅,主热储层埋深0～300 m.地热流体化学类型以HCO3-Ca·Na型和HCO3-Ca型为主,其次为SO4-Ca·Na型和HCO3·SO4-Na型,溶解性总固体85～1 284 mg/L,实测水温为25.4～79.9℃.热水氢氧同位素组成表明,大气降水为主要的补给来源,补给高程为57～584 m;13C同位素分析表明,地热水中碳的来源具有多重性,未受到碳酸盐变质作用的影响,根据14C方法测定地热水的年龄介于1.62～14.29 ka.二氧化硅(玉髓)温标热储温度为72～120℃,循环深度为1 814～3 504 m.热储受断裂带和碳酸盐岩层位控制,总体呈带状兼层状,热源为相对较高的大地热流和花岗岩体的放射性生热.以上认识揭示了广东龙门地区岩溶热储特征及地热系统成因机理.
Guangdong Province in south China is rich in geothermal resources and has a wide distribution of karstic heat reserves,which have great potential for exploration and development.The study for the mechanism of karstic geothermal system is expected to provide guidance to the exploration,development,and utilization of karstic reservoir in Guangdong Province and even in southern China.We took advantage of strengths in geological survey,borehole logging,and hydrogeochemistry to analyze systematically the characteristics of karstic reservoir and to understand the mechanism of the geothermal systems in the Longmen area of Guangdong Province.The analysis indicates that karstic aquifers in the study area are mainly hosted by carbonate rocks in caves and fissures of the Lower Carboniferous Shidengzi Formation(C1sh)and Upper Devonian Tianziling Formation(D3t)in the Longmen and Yonghan graben basins.The major karstic aquifers are characterized with shallow burial depths of 0～300 m.The chemical types of geothermal fluids are mainly HCO3-Ca·Na and HCO3-Ca,with a few SO4-Ca·Na and HCO3·SO4-Na types.Total dissolved solid and the measured temperature of geothermal water range from 85 mg/L to 1 284 mg/L and from 25.4℃to 79.9℃,respectively.Isotopic compositions of hydrogen and oxygen of thermal water indicate that geothermal water in the Longmen area is recharged by local precipitation and the elevations of recharge areas are in the range of 57～584 m.The analysis of carbon isotope(13C)reveals multiple sources of carbon which is unaffected by metamorphic of carbonate rocks.The residence time of geothermal water in the study area with 14C dating is 1.62～14.29 ka.The chalcedony geothermometer indicates a reservoir temperature between 72℃and 120℃.It is estimated that geothermal fluid can circulate at the depth from 1 814 m to 3 504 m.The reservoirs in the study area are controlled by fault zones and carbonate rock strata,and are generally banded and layered.The relatively high heat flow and high radioactive heat production rate of the widespread granites are considered as the heat sources of the geothermal system in the Longmen area.These findings reveal the characteristics of karstic reservoir and mechanism of geothermal system in Longmen area of Guangdong Province,South China.
张敏;魏正安;黄少鹏;王帅;何沛欣;覃夏南;唐灵
广东省有色金属地质局九三五队,广东惠州 516001深圳大学土木与交通工程学院,深地科学与绿色能源研究院,广东深圳 518060中国地质大学(武汉)资源学院,湖北武汉 430074
地球科学
地热资源岩溶热储控热构造热储温度同位素水文地球化学
geothermal resourcekarstic reservoirgeothermal-controlling structurereservoir temperatureisotopehydrogeochemistry
《深圳大学学报（理工版）》 2024 (001)
10-21 / 12
National Natural Science Foundation of China(U20A2096);Longmen County Financial Fund Project(ZZHZCG202004,GXHZ2017005) 国家自然科学基金资助项目(U20A2096);龙门县财政资金资助项目(ZZHZCG202004,GXHZ2017005)
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