Occurrence Characteristics of Deep Geothermal Resources In A Large Geothermal Field In The Northern Binhai New Area, Tianjin

Tianjin is rich in geothermal resources with high degree of development and utilization. At present, most of the developed deep geothermal resources are located in the "convex in uplift " area, while few research was carried on the " convex in depression" area. Located in Qiaogu area of Ninghe uplift in Huanghua depression, the Wumishan formation of Jixian system regarded as thermal reservoir with the best resource endowment has been newly discovered, with high temperature (90-120 ℃) and shallow burial (2200-2800m), which is preliminally evaluated as a large geothermal field with medium-low temperature.The geological structure, geothermal field and the occurrence characteristics of deep geothermal resources in the study area are systematically summarized, by analyzing the data of regional geology, magnetotelluric sounding (MT), measuring temperature and geophysical logging of boreholes. The research results show that the geological structural are complex and the fault is developed, Hangu fault as an important channel for heat and water conduction in the study area; The geothermal field presents the distribution characteristics of "two high and one low", which corresponds to the spatial position of the two anticlines; The heat source is mainly from mantle and shell, atmospheric precipitation is the main source of hot water, and the mechanism type of heat transfer is mainly heat conduction. Based on the comprehensive study of the occurrence characteristics of deep geothermal resources in the area, a conceptual model of deep geothermal resources is established.