Research Of Geothermal Resources On Hot Dry Rock In Xujiaweizi Fault Depression,Songliiao Basin

The dry-hot rock geothermal resources in Songliao Basin are rich and have great utilization potential.However,at present,the dry-hot rock geothermal resources are in the stage of resource exploration,and there are few high-temperature geothermal resources found in China.In particular,no effective high-temperature geothermal resources are found in the large-scale sedimentary basins in the east.Aiming at the key scientific problem of whether high temperature geothermal system can be formed in the middle and deep parts of sedimentary basins in eastern China,Xujiaweizi area of Daqing with high geothermal field is selected as the study area.Based on the study of regional geological characteristics of Xujiaweizi area,combined with oil test and logging data,the geothermal gradient characteristics of 3?6 km formation in the study area are analyzed.According to TCS thermal conductivity scanner,the thermal conductivity of rocks at different depths in different regions of the fault depression was tested.The characteristics of geothermal field in Xujiaweizi fault depression are analyzed.Through systematic rock thermophysical property test,combined with oil and gas test data of exploration wells and production wells in deep oilfield,the prediction method of deep formation temperature is established,and the characteristics of deep formation ground temperature field are described in detail.The variation law of formation temperature and the main control factors of formation temperature distribution are determined.The distribution range of the base radioactive heat source was determined by determining the old and new granites of the heat source rock.The proportion of dry hot rock geothermal resources is predicted by temperature,formation thickness,geothermal anomalies and different regions.The favorable area suitable for mining geothermal resources of dry hot rock in deep area is determined.Through the prediction of geothermal resources of dry-hot rock in Xujiaweizi fault depression,the upper and lower limits of recoverable resources of dry-hot rock geothermal resources in Xujiaweizi fault depression are determined.The results show that,(1)the basement depth of Xujiaweizi fault depression is 3200?4500 meters.The cover layer is thick and the surface temperature gradient is large,and the temperature increase is stable.There are a large number of volcanic reservoir rocks in the fault depression,and dry hot rock geothermal resources are rich.(2)Different structures in Xujiaweizi fault depression are affected by depth and lithology,and the thermal conductivity of rocks is different.The thermal conductivity of Fengle uplift is higher than 2.631W/m·K.(3)The total amount of dry-hot rock geothermal resources in the depth range of 3?6km in Xujiaweizi fault depression is 384.2×10¹⁹J,which is equivalent to 1311.97×10⁸t of standard coal.According to 2%of dry-hot rock geothermal resources as the lower limit of recoverable resources,the lower limit of recoverable resources in Xujiaweizi fault depression is7.68×10¹⁹J,which is equivalent to 2.62×10⁸t of standard coal.According to the calculation results,the dry-hot rock geothermal resources in Xujiaweizi fault depression are large and have great potential for utilization.(4)The favorable areas for dry-hot rock exploration in Xujiaweizi fault depression are mainly the Shengping-Songzhan uplift area in the central part and the Fengle uplift area in the.The bedrock surface is shallow and the geothermal gradient is high.