Discussion on the Geological Structure Characteristics and the Geothermal Formation in Jinghai County, Tianjin

There are abundant under ground geothermal resources in the Jinghai district,southwest Tianjin.In order to identify geothermal origin and make better use of local geothermal resources,the geological background,geothermal reservoir characteristics,isotope and geothermal genesis are studied.It is suggested that the geothermal reservoirs belong to a sedimentary basin type reservoir,which can be divided into two kinds.One is sandstone porosity type,and the other is bedrock fissure type.Three different geothermal reservoirs can be distinguished,namely,the Minghuazhen and Guantao group of the Neogene,and Ordovician Group of Paleozoic geothermal reservoirs.The water is from atmospheric precipitation of the northern mountainous area.The geothermal reservoirs have a good development condition,because there is thick Cenozoic cap rock which can preserve the deep heat for the deep geothermal reservoirs.