河北廊坊南部地区地热水化学特征及成因机制

The hydrochemical characteristics of geothermal water and its formation in the south Langfang,Hebei Province

地热资源的开发利用带来了良好的经济效益和社会价值,但不合理地开发利用地热资源,会对地表水及浅层地下水造成重大污染。通过水化学分析和水文地球化学模拟手段,分析了廊坊南部地区地下热水水化学特征及水质的成因机制。研究表明:新近系孔隙热储中,明化镇组热储地下热水主要水化学类型为HCO_(3)-Na型、HCO_(3)·Cl-Na型;馆陶组热储地下热水水化学类型以Cl-Na型、Cl·HCO_(3)-Na型为主,该层水力联系较好,地热水径流区内主要水岩作用为硫酸盐、硅酸盐矿物的溶解作用,以及阳离子交替吸附作用。基岩裂隙热储地下热水水化学类型为Cl-Na型,该层水力联系较弱,阳离子交替吸附作用是水化学演化的主要水岩相互作用。基于PHREEQC的水文地球化学定量模拟,揭示了地质背景、水文地质条件及人类活动因素共同控制的地下热水的流场和水岩相互作用的程度,在研究廊坊地区地热水水化学演化机理及地热水动态特征方面具有一定的意义。

The exploitation and utilization of geothermal resources bring good economic benefits and social value,but the unreasonable exploitation and utilization of geothermal resources could cause serious pollution to surface water and shallow groundwater.By means of hydrochemical analysis and hydrogeochemical simulation,the hydrochemical characteristics of geothermal water and its formation in the south of Langfang were analyzed.The results show:In Neogene system the main chemical types of geothermal water in the Minghuazhen group were HCO_(3)-Na and HCO_(3)·Cl-Na.The chemical types of the geothermal water in the Guantao group were mainly Cl-Na and Cl·HCO_(3)-Na.In this layer,the hydraulic connection is relatively good,and the main water-rock action in the geothermal water runoff area is the dissolution of sulfate and silicate minerals,and the cationic alternating adsorption.The hydrochemistry of geothermal water in bedrock fissure thermal storage is Cl-Na,the hydraulic relation of this layer is relatively weak,and the cationic alternating adsorption is the main water-rock interaction in its hydrochemical evolution.Hydrogeochemical quantitative simulation based on PHREEQC reveals that geological background,hydrogeological conditions and human activity factors jointly controlling the degree of flow field and water-rock interaction of underground hot water,which is of certain significance for studying the hydrochemical evolution mechanism of geothermal water and the dynamic characteristics of geothermal water in Langfang area.