天津周良庄地质构造背景和地热成因探讨

Discussion on the geological tectonic setting and geothermal origin in Zhouliangzhuang area of Tianjin

天津市宝坻区南部周良庄一带赋存较为丰富的地热资源。为查明该区各热储补给来源,地温场是否受断裂构造影响,利用人工地震结合钻探资料进行二次解译,分析该区地质构造背景和热储发育特征,同时在综合分析水化学和同位素等化探方法的基础上,对该区的地热成因进行探讨。查明该区主体构造为一背斜构造,地热属沉积盆地型层状热储,地热流体主要有孔隙型热水系统和基岩裂隙型热水系统2个类型,热储条件好。该区热流体矿化度较低的原因是接近补给区,补给水源来自北部山区大气降水;地热流体在深循环过程中与富氧岩石进行了氧交换,δ18O值存在不同程度的氧漂移。

There is plentiful geothermal resources in Zhouliangzhuang of southern Baodi of Tianjin.In order to identify the geothermal origin and the geothermal field whether affected by fault structures,the authors performed secondary interpretationon using artificial earthquake and drilling data,and analyzed the geological tectonic setting and developing characteristics of geothermal reservoir,and discussed the geothermal origin on the basis of hydrochemistry comprehensive analysis and isotope geochemical exploration.It is concluded that the main structure in this area is an anticline,the geothermal belongs to a sedimentary basin-type layered geothermal reservoir,which has two types with good conditions,including porosity-type and bedrock fractured-type hot water systems.Being close to the supply area is the reason of low salinity in this area,and the water supply comes from atmospheric precipitation in northern mountain area.Geothermal fluid exchanged the oxygen with rich oxygen-bearing rocks in deep-cycle process and δ18O existed with the oxygen shifting in various degrees.