摘要
湖南省目前地热井多为深度较小(多在500 m以浅)的热对流型,用地热井测温数据求取的地温梯度一般偏大很多。为解决对流型地热测得的地温梯度偏大问题,本文采用地热温标、管道模型及基于生热率的深部地温反推法等地温梯度估算方法,综合确定了湖南省现今的地温梯度。结果显示,湖南省高地温场大致沿中部的白马山岩体、沩山岩体、幕阜山—黄龙山岩体一线和湖南省东南部分布,地温梯度大于3.0℃/100 m;5000 m深度、6000 m深度沩山岩体、热水圩一带的最高温度分别达到了218.69℃、216.70℃和258.99℃、256.60℃。深大断裂与多块体接合部位的构造形态相配合,使湖南省中部构造交汇带处于张开性的构造环境,有利于大气降水的深循环与深部热物质的上侵,是形成湖南省中部高地温场的主要原因。湖南省东南部是西太平洋板块俯冲与回撤的前缘,处于江南造山带与华夏板块的接合带,有利于大气降水的深循环与深部热物质的上侵;同时高放射性生热率的铀矿床、矿点也提供了较高的地壳热量,是形成湖南省东南部高地温场的主要原因。地温梯度及地温场的科学界定,为湖南省下一步寻找高温地热资源指明了方向。
At present,most geothermal wells in Hunan Province are thermal convection type with small depth(mostly shallow 500 m),and the geothermal gradient obtained from the temperature measurement data of geothermal Wells is generally much larger.In this paper,geothermal temperature scales,pipeline models,and deep geothermal temperature back-calculation methods based on the heat generation rate were used to estimate the geothermal gradient.The present geothermal gradients in Hunan Province were comprehensively determined.The high value geothermal field in Hunan Province is approximately located along the line of Baishan granitoid pluton,Weishan granitoid pluton,Mufushan granitoid pluton,and Huanglongshan granitoid pluton.The geothermal gradient in the southeast of the Hunan Province is greater than 3.0℃/100 m.The highest temperature of the Weishan granitoid pluton and Reshuiwei area at 5000 m depth and 6000 m depth reached 218.69℃,216.70℃and 258.99℃,256.60℃,respectively.The combination of deep and large faults with the structural configuration of the joint part of multi-blocks makes the structural convergence zone in central Hunan Province in an open tectonic environment.This is conducive to the deep circulation of atmospheric precipitation and the intrusion of deep thermal material.This is the main reason for the formation of the high geothermal field in the central Hunan Province.The southeast of the Hunan Province is in front of the subduction and retraction of the West Pacific plate and is located in the junction zone between the Jiangnan orogenic belt and the Cathaysia plate,which is conducive to the deep circulation of atmospheric precipitation and the upwelling of deep thermal materials.Uranium deposits with a high radioactive heat generation rate also provide high crustal heat,which is the main reason for the formation of the high geothermal field in southeastern Hunan Province.The scientific definition of geothermal gradient and geothermal field points provide the direction for locating high temperature geothermal resources in Hunan Province.
作者
欧健
皮建高
张保建
唐显春
周华
高俊
白华青
王思琪
欧任文
黄郁淇
皮景
文娟
OU Jian;PI Jian-gao;ZHANG Bao-jian;TANG Xian-chun;ZHOU Hua;GAO Jun;BAI Hua-qing;WANG Si-qi;OU Ren-wen;HUANG Yu-qi;PI Jing;WEN Juan(Hunan Geological Disaster Investigation and Monitoring Institute,Changsha,Hunan 410004;Chinese Academy of Geological Sciences,Beijing 100037;Technology Innovation Center of Geothermal and Hot Dry Rock Exploration and Development,Ministry of Natural Resources,Shijiazhuang,Hebei 050061)
出处
《地球学报》
CAS
CSCD
北大核心
2023年第3期543-557,共15页
Acta Geoscientica Sinica
基金
湖南省地质院科研基金项目(编号:HNGSTP202102)
国家自然科学基金项目(编号:41902310)
中国地质调查局地质调查项目(编号:DD20221677,DD20189114)联合资助。
关键词
放射性生热
地温梯度
地温场
湖南省
radioactive heat generation
geothermal gradient
geothermal field
Hunan Province
