Preliminary Study On EGS Geothermal Resources Evaluation And Exploration In Song-Liao Basin

With the rapid development of social economy,energy shortage has become increasingly prominent.Traditional coal,oil and gas resources are scarce,the contribution of development and use to the greenhouse effect and the pollution of the ecological environment are becoming increasingly apparent.In the increasingly severe situation,solar energy,wind energy,geothermal energy and other new energy came into being.Among them,geothermal energy because of its huge reserves,widely distributed by experts and scholars of various countries attention.However,the development and utilization of geothermal energy is still faced with a series of technical problems.For example,the appropriate hot and dry rock(Hot Dry Rocks)constituency to determine the deep drilling technology,fracturing technology.Songliao Basin is located in northeastern China,across the three northeastern provinces,a small part of the territory of Inner Mongolia.The basin belongs to the continental margin of the continental rift basin,the basin can be divided into upper and lower layers,the lower formation date about 650 Ma,mainly containing gneissic granite and deep metamorphic rocks,the upper row time is about 135 ~ 350 Ma,mainly contains shallow metamorphism Rock and granite.The basement thickness of the basin is about 11 km,and the Cretaceous dominates.The average heat flux in the northeastern region is 68.78 m W / m2,and the geothermal flow in the Songliao Basin is between 51.5 and 90 m W / m2.The basin is gradually increasing from shallow to deep,and moved from the northeast of the basin to the southwest.The average geothermal gradient of the main part of the basin is 3.8 ? / 100 m,and the geothermal gradient is between 3.0 ~ 5.0 ? / 100 m,and the geothermal gradient in Daqing-Baicheng area is higher.Enhanced Geothermal System(EGS)is the exploitation of dry and hot rock engineering.In this paper,based on the special project of "Deep Hydrogeological Survey in Northeast China",this paper carried out the preliminary study on EGS geothermal resources evaluation and survey and development of Songliao Basin,based on the study of regional geological conditions,Logging data,the use of Arc GIS tools,the volume method to calculate the basin geothermal resources,Songliao Basin dry hot rock resources for the total 0.62 ?106EJ.Based on the analysis of regional geology and geophysical analysis,the factors such as "heat source","resource quantity","heat conduction","heat gathering","earthquake activity"," The results show that there are eight depth factors in the Songliao Basin,which have different depth logging data in the Songliao Basin.The results show that there are eight factors in the buried depth,the basal rock formation rate,the fissure density,the thermal conductivity,the folds,the mudstone thickness,the geothermal resource density and the seismic intensity.26 wells were used to divide the basin into 26 evaluation units by using the Tyson polygon method.The weights of the eight evaluation factors were obtained by using the analytic hierarchy process.Each evaluation factor was scored according to the expert scoring method,and the evaluation factors were multiplied by the corresponding The evaluation results are in accordance with the appropriate-more appropriate-general fit-less suitable-not suitable to the results of the division,the most suitable as the EGS survey and development The location of the constituency is probably in Da'an to Daqing area.Limited to the accuracy of data,according to the method identified in this article EGS survey and development of the scope of the election is too large,according to foreign experience,the use of geophysics to further narrow the scope.The seismic method can well detect the regional strata,providing higher resolution for the stratigraphic unit,but the seismic imaging is less permeable and costly.This method is suitable for detecting the structure above the EGS rock mass.The rapid development of science and technology to promote the rapid development of electrical law,electromagnetic method can find low resistance,although the low resistance is not necessarily a fluid,but in the vicinity of low resistance anomalies associated with low density or low seismic velocity,then the low resistance is the probability of fluid Bigger.The gravitational method can be well determined by the longitudinal density difference in the location to determine the sedimentary basin boundaries or longitudinal faults.The aeromagnetic field can determine whether the vertical fracture exists in the crystallization unit and provide an important reference for the specific construction location of the EGS.Using these methods,we can further verify the reliability of this conclusion by further conducting geophysical exploration of Da'an-Daqing area,delineating the possible areas of dry calorie with larger scale,and drilling with relevant projects.