深圳大学学报（理工版）2024，Vol.41Issue(1)：10-21,12.DOI:10.3724/SP.J.1249.2024.01010
广东龙门地区岩溶热储特征及地热系统成因
Characteristics of karstic reservoir and mechanism of geothermal system in Longmen area of Guangdong Province,China
摘要
Abstract
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.关键词
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Key words
geothermal resource/karstic reservoir/geothermal-controlling structure/reservoir temperature/isotope/hydrogeochemistry分类
天文与地球科学引用本文复制引用
张敏,魏正安,黄少鹏,王帅,何沛欣,覃夏南,唐灵..广东龙门地区岩溶热储特征及地热系统成因[J].深圳大学学报（理工版）,2024,41(1):10-21,12.基金项目
National Natural Science Foundation of China(U20A2096) （U20A2096）
Longmen County Financial Fund Project(ZZHZCG202004,GXHZ2017005) 国家自然科学基金资助项目(U20A2096) （ZZHZCG202004,GXHZ2017005）
龙门县财政资金资助项目(ZZHZCG202004,GXHZ2017005) （ZZHZCG202004,GXHZ2017005）
