浅析北京市延庆区西北部地热地质特征

Analysis on Geothermal Geology Characteristics in the Northwest of Yanqing District, Beijing

为解析延庆区西北部地区的地热地质特征,本文通过对研究区内的地热流体通道、热储层和盖层条件的总结分析,并综合地温场分布特征和地热流体化学特征,浅析了研究区内的地热资源形成条件。结果表明,研究区内的NEE向与NS向断裂为主干断裂,在其交互处,形成主要的热水通道,发育了以蓟县系雾迷山组为代表的层状热储,地热流体主要来源于1.5～4.6万年前的大气降水补给,与浅层地下水几乎无水力联系。延庆盆地内的地热资源主要受以热传导为主的传热过程控制,热储层和盖层岩石热导率的差异,使得平面上的温度差异显示出受控断裂构造控制的趋势。

In order to obtain the characteristics of the geothermal geology in the northwest of Yanqing District, Beijing, the article summarizes the condition of the geothermal fluid channel, geothermal reservoir and cap rock in the studying area, combining the distribution characteristics of geothermal field and chemical characteristics of geothermal fluid, and analyzes the forming conditions of the geothermal resources. The result indicates that main geothermal fluid channel was formed in the cross points of the main faults including the NEE-striking and NS-striking faults in the studying area. Meanwhile stratified reservoir represented by Wumishan Fm. of Jixian System is controlled by the faults in the studying area. Geothermal fluid mainly from the recharge of the old meteoric water is aged from 15,000 to 4,6000 years old, hardly having hydraulic connection with the groundwater from the Quaternary aquifer and shallow base rock aquifer. Geothermal resources in the Yanqing Basin are mainly controlled by heat transfer process dominated by heat conduction. For the difference of thermal conductivity between geothermal reservoir and cap rock, the temperature difference in the plane shows the tendency controlled by the faults.