沂沭断裂带地热资源特征及成因分析——以山东省临沂城区地热为例

Analysis on Characteristics and Origin of Geothermal Resources in Yishu Fault Zone——Taking Geothermal Resources in Urban Area in Linyi City in Shandong Province as an Example

临沂城区位于沂沭断裂带西侧,沂沭断裂带是一条巨型新华夏系断裂构造带。临沂城区赋存着丰富的地热资源,通过对研究区地球物理勘探、地温测量、水质分析等资料的研究,分析了研究区地热地质特征,论述了地热资源成因。临沂城区东北部热储类型为基岩构造裂隙带状热储,地热水类型为基岩构造裂隙水,补给来源为大气降水,沂沭断裂带及其次一级断裂为导水、导热构造,浅部地下水经过深循环后被加温形成地热资源。地热水主要为溶滤型的陆相沉积水,水化学类型为Cl-Na·Ca型,地热水中常规组分随热储层深度的增加而增大。选择钾镁地球化学温标和无蒸汽损失的石英温标计算热储温度在78~104℃,为中低温热储,为断裂控制的深循环对流型地热田模式。

Linyi city is located in western Yishu fault zone.It is a giant Neocathaysian fault zone.There are rich geothermal resources in Linyi city.Through geophysical exploration,geothermal measurement and water quality analysis,geological characteristics of geothermal resources in the study area have been analyzed,and the origin of geothermal resources has been discussed.Geothermal reservoirs in the northeastern Linyi city is bedrock structural fissure type,geothermal water is bedrock structural fissure type,and the recharge source is atmospheric precipitation.Yishu fault zone and its secondary faults are water and heat conduction structures.After deep circulation,the shallow groundwater is heated to form geothermal resources.The geothermal water is mainly dissolved and filtrated continental sedimentary water,and hydrochemical type is Cl-Na·Ca.The conventional components of geothermal water will increase accompanying with the depth of thermal reservoir.By using geochemistry temperature scale and the non-steam loss quartz temperature scale of K and Mg,the temperature of the thermal storage is calculated as 78~104℃.It is a medium low temperature heat storage,and a deep circulation convection geothermal field model controlled by faults.