河北平泉低温地热资源水文地球化学特征及成因  

Hydrogeochemical characteristics and genesis of the low geothermal resources in Pingquan of Hebei

作　　者：孙双振 朱炎 赵青松 金双 杨万顺 贺晓东 田放 朱元卓 SUN Shuangzhen;ZHU Yan;ZHAO Qingsong;JIN Shuang;YANG Wanshun;HE Xiaodong;TIAN Fang;ZHU Yuanzhuo(The Fifth Geological Brigade of Hebei Bureau of Geology and Mineral Resources,Tangshan 063000,China)

机构地区：[1]河北省地质矿产勘查开发局第五地质大队(河北省海洋地质环境调查中心),河北唐山063000

出　　处：《世界核地质科学》2024年第5期919-934,共16页World Nuclear Geoscience

基　　金：河北省公益性地质工作项目(2024)(编号:13000024P00F2D410449K)资助。

摘　　要：河北承德地热资源丰富,然而平泉地区地热资源的研究几乎处于空白状态,从水化学角度系统研究地热水的演化机理,对该地区地热资源的开发利用具有重要意义。根据地热水和冷水的水质指标,运用离子比率、同位素分析、地球化学温标以及硅-焓模型等方法,圈定地热水的水化学特征、分析地热水的储存条件和补给来源、定量评估研究区热储温度、冷水混合比例和循环深度。结果表明:该区地热水的水化学类型为HCO3-Ca·Mg;地热水的补给来源是大气降水,其为古地下水和现代水的混合产物,经历深循环且循环速度较慢;该区的热储温度介于65.9~74.5℃之间,冷水混合比例为79%,未混入冷水时深部热储温度为125℃。该区地热水接受大气降水补给,沿风化裂隙和断裂进入地下深部,在大地热流背景下不断被加热,赋存于裂隙发育的断裂破碎带中,在静水压力和热动力驱动下沿断裂破碎带和岩性接触带上升,在浅部与冷水混合,形成低温地热资源。Chengde municipality in Hebei province has abundant geothermal resources,but the study on the resources in the subordinate Pingquan area are quite limited,therefore,comprehensive hydrochemical study on the formation processes of geothermal waters is essential for the geothermal resources exploitation in the Pingquan area.Based on the water quality indicators of geothermal and cold waters,this paper employed the methods of ionic ratios,isotopic analysis,the geochemical temperature scale and the silica-enthalpy model to delineate the hydrochemical characteristics of geothermal waters.Furthermore,the study analyzed the storage conditions and the recharge sources,and employed a quantitative assessment of the thermal storage temperature,cold water mixing ratio,and depth of thermal cycling in the study area.The results showed that the hydrochemical type of geothermal waters in the area was HCO3-Ca·Mg.The principal recharge source for the geothermal waters was atmospheric precipitation,comprising a mixture of ancient and modern groundwater undergoing slow deep circulation.The thermal storage temperature in the area ranged from 65.9 to 74.5°C,with a cold water mixing ratio of 79%.And without the mixing of cold water,the deep thermal storage temperature could reach 125°C.The geothermal waters in Pingquan were recharged by atmospheric precipitation,which infiltrated deep underground along waterconducting fractures and zones.These waters were continuously heated by the Earth's geothermal flux and stored in well-developed fracture zones.Driven by hydrostatic pressure and thermodynamic forces,it ascended through fracture zones and lithological contact zones,mixing with cold waters in the shallower parts of the crust to form low temperature geothermal resources.

关 键 词：地热水 地球化学特征 成因模式 热储温度 平泉 

分 类 号：P641.3[天文地球—地质矿产勘探]