西藏南北地堑典型地热田水化学特征与热储温度空间分布规律  

Hydrogeochemical characteristics and spatial distribution of reservoir temperature in the north-south trending grabens of southern Xizang

作　　者：周金林 王迎春 范宇和 全三余 罗璐 宋荣彩[1] ZHOU Jinlin;WANG Yingchun;FAN Yuhe;QUAN Sanyu;LUO Lu;SONG Rongcai(College of Energy(College of Modern Shale Gas Industry),Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Chengdu University of Technology,Chengdu 610059,China;Institute of New Energy,Sinopec Star Petroleum.,LTD.,Beijing 100083,China)

机构地区：[1]成都理工大学能源学院(页岩气现代产业学院),成都610059 [2]油气藏地质及开发工程全国重点实验室(成都理工大学),成都610059 [3]中国石化集团新星石油有限公司新能源研究院,北京100083

出　　处：《成都理工大学学报(自然科学版)》2025年第2期223-235,I0001-I0003,共16页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金项目(42130809,42372301)。

摘　　要：西藏南北地堑系位于地中海-喜马拉雅地热带核心部位,其间发育了众多高温地热系统。然而,地堑系控制的地热系统流体地球化学演化特征及热储分布规律仍不清楚。对申扎-定结、亚东-谷露和错那-沃卡3个典型地堑系内15个地热系统通过地质调查、水文地球化学采样测试并结合258个热泉文献数据,分析了地热水地球化学演化过程,估算了各个地热田不同储层温度。结果表明:(1)研究区北部地热水主要为HCO_(3)-Na和Cl-Na型,南部为Cl-Na型,水化学类型差异受流体循环深度、冷热水混合比例、水−岩相互作用和矿物溶解沉淀等过程控制;(2)研究区北部地热水补给源为大气降水、冰雪融水和深部岩浆水,而南部则为大气降水和冰雪融水补给为主;(3)地热田储层温度在平面上整体表现为北高南低且亚东-谷露地堑温度相对较高;垂向上表现为北部2个高温热储(储层温度180~220℃和240~300℃)和1个中温热储(100~140℃),而南部为2个高温热储(150~180℃和240~260℃)。研究结果对理解藏南地堑系高温地热系统成因机制及指导地热资源开发利用具有重要意义。Many high-temperature geothermal systems have developed in the north-south trending graben system of southern Xizang,which is located at the middle of the Mediterranean-Himalayan geothermal belt.However,the evolutionary characteristics of the fluid geochemistry and the distribution of reservoir temperature in grabencontrolled geothermal systems are poorly understood.In this paper,the geochemical characteristics of thermal water from 15 geothermal systems in selected grabens(Shenzha-Dingjie,Yadong-Gulu,and Cuona-Woka)are analyzed through a combined geological survey,hydrogeochemical sample measurements,and data compiled from 258 hot springs.The reservoir temperatures of different geothermal fields are estimated using geochemical geothermometer measurements.The results indicate that the water in the thermal spring from the northern grabens is HCO_(3)-Na and Cl-Na type,while that in the southern part is Cl-Na type.The depth of fluid circulation,the mixing ratio with cold groundwater,water-rock interactions,and the dissolution and precipitation of mineral are all factors controlling the water type.Meteoric water,snow meltwater,and magmatic water are the water sources of the hot spring in the north graben,while the sources of the hot spring in the south part are meteoric water and snow meltwater.The reservoir temperature of the geothermal field is characterized by being higher in the north and lower in the south,and the thermal reservoir in the Yadong-Gulu graben is the hottest.There are two high-temperature reservoirs with temperatures of 180~220℃ and 240~300℃ and one medium-temperature reservoir with a temperature of 100~140℃ in the north part,while there are two high-temperature reservoirs with temperatures of 150~180℃ and 240~260℃ in the south.The results in this paper allow us to determine the genesis mechanism of high-temperature geothermal systems in graben systems,which provides guidance for the exploitation and utilization of geothermal resources.

关 键 词：藏南地堑系 水化学演化 氢氧同位素 热储温度 空间特征 

分 类 号：P314[天文地球—固体地球物理学]