Study On Mechanical Properties Of Argillaceous Shale Under Temperature

Shale gas has abundant reserves on the earth,and is currently a key research target for exploration and development in various countries around the world.It is widely distributed in China,so it is a hot resource for domestic energy supply in the future.However,shale gas is produced from shale.At the same time,shale is still the shale gas reservoir and cap rock.Therefore,the physical and mechanical characteristics of shale have a direct impact on the development of shale gas.However,there are few studies on the thermo-mechanical coupling effects of deep shale,and the experimental conditions are limited.Therefore,the effects of different thermal forces on the mechanical properties of shale and their brittleness evaluation index are studied by uniaxial compression test and real-time triaxial compression test under high temperature and high pressure,as follows:?1?Uniaxial compressive strength tests were performed on argillaceous shale at room temperature to study its uniaxial compressive strength,and triaxial indoor compression tests were performed on argillaceous shale under different real-time temperatures.With different real-time temperature effects,the mechanical properties show different laws.This indicates that the physical and mechanical characteristics of argillaceous shale have a strong temperature effect;moreover,When the confining pressure is continuously increased,the main controlling factors of the brittle-delay transition of the shale will be changed.The higher the confining pressure applied,the greater the effect of temperature effect.?2?The high temperature and high pressure rock triaxial test system is used to test argillaceous shale under different real-time temperatures,and a new energy brittleness evaluation coefficient B based on rock energy conversion balance is proposed.The evaluation coefficient consists of peak strength and residual strength,Multi-factors such as elastic modulus,peak strain,and residual strain were established.The brittleness evaluation coefficient can better analyze the brittleness of the argillaceous shale triaxial compression test results under real-time high temperature and pressure,and establish the coupling relationship between the brittleness evaluation coefficient and thermomechanical force.?2?Based on the Weibull distribution rock damage constitutive model,the model parameters of mud shale under real-time high-temperature and high-pressure triaxial compression test data are calculated and compared to fit analysis.The research shows that the model's peak point and the pre-peak climbing phase fit relatively well,but the post-peak residual strength level for the brittle mud shale is poorly fitted.The surface parameters were fitted to the model parameters and it was found that under a certain confining pressure,the value of the model parameter M changed to an "N" shape.And it was found that the model parameter F₀ has a similar trend in peak intensity under thermo-mechanical coupling at 200 ° C,indicating that the value of F₀ has a greater relationship with the triaxial compressive strength.The change in peak intensity directly affects the value of F₀...