Study On The Variation Of Thermal Recovery Performance Of Granite Thermal Reservoir Considering Different Injection Production Parameters

At present,there are various engineering bottlenecks in the enhanced geothermal system（EGS）projects in China.For example,low exploration degree,insufficient heat transfer technology,high cost of high temperature drilling,the risk of inducing micro earthquake.All of the above is closely related to the unclear understanding of the reservoir parameters.And the variation law of heat production performance under different injection and mining parameters is closely related.Taking the granite thermal reservoir in Daqing area in northern Songliao Basin.By measuring the physical,mechanical parameters,permeability of granite in Songliao Basin at different high temperatures.The measured parameters were imported into the numerical simulation software.This software is a multi-physical field-coupled numerical software.The temperature seepage coupling model is established.The influence law of different injection and mining parameters on reservoir production capacity and reservoir stability is obtained.Injection and mining parameters include injection temperature,distance between production wells and crack inclination.Finally,it provides a scientific reference for EGS thermal mining in Songliao Basin.This reference can improve production capacity and avoid micro earthquake occurrence.The important conclusions of the paper research are as follows:（1）As temperature increases,the mass and elastic modulus of the granite is reduced.As temperature increases,the volume of the granite first decreases and then increases.As temperature increases,the density,porosity,compressive strength,Poisson ratio of the granite first increase and then decrease.The study points out that the higher the temperature,the weaker the granite deformation ability.And the higher the temperature,the easier the deformation to produce under external force.（2）Measure the granite permeability after different high temperatures with CO₂.As the temperature increases,the granite permeability changes in an exponential function.Granite permeability decreases as the volume stress increases.To ensure the reservoir connectivity,the high temperature area with shallow buried depth should be selected as the hot mining target area.（3）With the increase of injection temperature,well distance between production Wells,crack inclination Angle,the reservoir production capacity increases.And the reservoir stability changes irregularly.If considering increasing the reservoir capacity,high injection temperature,large distance between production Wells and large crack inclination should be selected.If the reservoir stability is considered,a higher injection temperature should be selected.And the optimal distance between the production Wells is 700m,the optimal fracture inclination is 0°.There are 48 figures,10 tables and 158 references in this paper.