藏北温泉盆地地热田水文地球化学特征研究  

Hydrogeochemical characteristics of the geothermal field in Wenquan basin,northern Tibet

作　　者：徐刚[1] 伍坤宇[2,3] 王鹏 陈永东 李兴彦[3] 胡林 刘子畅 李海[1] XU Gang;WU Kunyu;WANG Peng;CHEN Yongdong;HU Lin;LIU Zichang;LI Hai(Northwest Sichuan Geological Team,Sichuan Bureau of Geology and Mineral Resources,Mianyang,Sichuan 621000,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Qinghai Oil Field Branch Company,CNPC,Dunhuang,Gansu 736202,China;Institute of Groundwater and Earth Sciences,Jinan University,Guangzhou,Guangdong 510632,China;Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]四川省地质矿产勘查开发局川西北地质队,四川绵阳621000 [2]西南石油大学油气藏地质与开发工程国家重点实验室,成都610500 [3]中国石油青海油田分公司,甘肃敦煌736202 [4]暨南大学地下水与地球科学研究院,广州510632 [5]成都理工大学,成都610059

出　　处：《中国岩溶》2020年第3期299-310,共12页Carsologica Sinica

基　　金：国家自然科学基金(51709127);广东省自然科学基金(2017A030310172);中国地质调查局“青海龙亚拉地区1/5万I46E017008、I46E017009、I46E018008、I46E018009四幅区调(1212011221019)”项目资助。

摘　　要：藏北温泉盆地地热资源丰富,但研究程度较低。为查明温泉盆地地热资源赋存状态及热源来源,揭示热循环机理,定量评估研究区热储温度、冷水混入比例、热循环深度等,利用温泉盆地地热田共18组温泉水样进行水化学分析,进行定量计算。结果表明:温泉盆地温泉水水化学类型主要为Ca-HCO3·SO4型。温泉盆地地下热水在向上运移过程中,受浅层地下水的混合作用影响,使得热水变为“未成熟水”。温泉水中文石、方解石等钙质热液的饱和度指数大于0。热储温度60.93~96.52℃,热循环深度3238.06~5215.28 m,冷水混入比例在20.97%~70.19%之间。硅-焓模型计算出未混入冷水时深部热储温度在81.94~167.26℃之间,热储循环深度4405.56~9145.56 m。The Wenquan basin in northern Tibet is rich in geothermal resources,on which few studies were carried out previously.The purpose of this study is to clarify the occurrence and source of geothermal resources,reveal the mechanism of the thermal cycle,and quantitatively evaluate the temperature of the geothermal reservoirs,the mixing ratio of cold water and the depth of thermal cycle in this basin.A total 18 groups of hot spring water samples from the Wenquan basin geothermal fields were used for hydrochemical analysis and quantitative calculation.The results show that the thermal groundwater of the basin is dominated by the Ca-HCO3·SO4 type.In the process of upward migration,the geothermal water becomes"immature water"affected by the mixing effect of shallow groundwater.The saturation index(SI)of calcium hydrothermal minerals in hot spring water samples,such as aragonite and calcite,is greater than 0.The temperature of geothermal reservoirs is from 60.93 to 96.52℃,the depth of thermal cycle is from 3,238.06 to 5,215.28 m,and the mixing ratio of cold water ranges from 20.97% to 70.19%.The temperature and depth of geothermal circulation before mixing cold water are determined by the Sienthalpy model as 81.94 to 167.26℃ and 4,405.56 m to 9,145.56 m,respectively.These results can provide data support and theoretical support for the future geothermal research in northern Tibet,as well as a reference for the study of groundwater development and utilization in the study area.

关 键 词：水文地球化学 水-岩平衡 硅-焓模型 热储温度 热循环深度 温泉盆地地热田 

分 类 号：P314[天文地球—固体地球物理学]