| As a renewable clean energy,geothermal energy can bring huge benefits to the economic development of countries all over the world.Xianning City,Hubei Province is rich in medium and low temperature geothermal resources.This paper takes the Jiugong Mountain geothermal field in Tongshan County as the research object,and conducts analysis and research on the geological characteristics and genetic models of the geothermal field to give full play to the unique advantages of geothermal resources in this area.Local rural revitalization plays a key supporting role.The paper summarizes the lithology,geological structure,hydrogeological conditions and geothermal geological characteristics of the regional strata,combined with the geochemical radon gas measurement to deduce that there are many hidden faults that have not been discovered in the survey area,and combined with the geochemical radon gas measurement to deduce that there are no hidden faults in the area.Many hidden faults were discovered,and then the geophysical wide-area electromagnetic method was used to interpret the characteristics of the deep strata and the development characteristics of the faults.Through the SHK01 borehole with a depth of 2407.43m,the geothermal water with a water temperature of 50.3°C was successfully proved,and the water output was1230m~3/d.Through the pumping test of the geothermal well,it is determined that the unit water inflow of the well is 0.055-0.059L/s·m,the permeability coefficient is 0.00679-0.00786m/d,the thickness of the aquifer is 768.9m,and the thermal reservoir is weakly water-rich.Through the collection and analysis of water samples,the geothermal fluid is sodium bicarbonate-type weakly alkaline low-temperature water,in which the content of sodium ions and metasilicate is significantly higher than that of cold spring and river water,and through the analysis of isotopes,the altitude of the recharge area of the geothermal well Between 803m and 997m,the thermal storage temperature is determined to be 76.2℃by the silica temperature scale,and the thermal storage depth is estimated to be 2888m(equivalent to-2801m above sea level)by geothermal gradient.Finally,the genetic type of geothermal field belongs to hidden geothermal field based on the analysis of lithology results from previous exploration data and drilling.The source,ventilation,storage and cover conditions of the geothermal field are identified.The heat source of underground hot water belongs to deep heat source,which gradually absorbs geothermal energy through faults and cracks to form hot water.The main source of water recharge is near source recharge,which comes from exposed carbonate rocks of Jiugong Mountain in the south of the geothermal field and receives near source recharge of atmospheric precipitation,and groundwater participates in deep cycle migration into the area.The main geothermal channels are hidden faults F10,F11 and their regional secondary faults.The thermal reservoir is mainly composed of quartz sandstone,argillaceous siltstone and limestone.The cap bed is composed of silty shale and carbonaceous silty shale of Silurian Xintan Formation. |
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