Reserves Evaluation Of Geothermal Resource In Yinchuan Plain Based On3D Geological Modeling

Yinchuan plain contains huge reserves of geothermal resources. Based on theformation favourable condition of geothermal resources and the features of thegeothermal resources, this article evaluate the geothermal resources in Yinchuan plainthrough establishing the3D geological model and referencing the existing geothermalwells data.The avourable conditions in the format of geothermal resources are concluded byorganizing a large amount of materials, using the data of new geophysicalinterpretation, and sufficiently analying the characteristics of Yinchuan plain landform.The slope catachment provides the source for geothermal water through deep cycling.The very thick Cenozoic strata and specific lithologic properties creat the favorablereservoircap conditions. The deep and large active faults provide the channel for deepheat flow moving up. The uplifts gather thermal fluid and form high geothermanomaly area. The lung upper mantle asthenosphere and mantle flow with highthermal flow creat well deep heat source conditions. Then by analyzing thedistribution of geothermal field, this study shows that ground temperature can reach80℃within deep3000m, shallow geothermal gradient is enough big, the Yinchuanplain has great potential of low temperature geothermal resources.The premise of evaluating the geothermal resources is undersding the rechach areageological structure clearly. The3D geological model can show the spatial distribu-tion patternlandform, geological structure, stratum lithology intuitively. This can pro-vide the basis for dividing geothermal storage area, ensuring geothermal storageburied depth, dividing geothermal storage layers, evaluating geothermal storage thick-ness. The3D geological is builded in GOCAD software based on exploration holesdata and the geological structure profile interpreted from the earthquake and geophy-sical data.Under the economic and technical feasibility, divding the evaluated area of geo-thermal storage of the shallow geothermal gradient gradient above2.5℃/100m, geo-thermal storage gradient reach25℃, above the deep of4000m and the O ligocenebottom. The geothermal storage area is1990.473106m2. Using the geothermal re-source assessment method fitting geology features of research area, and divding thegeothermal storage area to5zones, this study finally calculats the totale geothermal resources is4518.7731014kJ, the totale allowable geothermal resources is1129.6931014kJ, the totale geothermal fluid storage is12742.773108m3, the totale allowablegeothermal fluid storage is637.173108m3. Through the assessment of economic andenvironmental impact to the development and utilization of geothermal resources, it iscan be concuded that the geothermal resources in study is economical; the standardcoal converted by geothermal resources is38.61×108t, and it can save the harnessingenvironment to10737.63billion yuan; as the hot reservoir is deep buride, it is lesslikely to cause ground subsidence by exploting geothermal fluid.This study has builded the3D geological model and evaluated geothermal resour-ces storage. The results provide important guiding significance for developing andusing the geothermal resources and realizing the sustainable development of energyand economy in Yinchuan plain.