Experimental Study On Permeability Characteristics Of Rock Under High Temperature And Triaxial State Of Stress

Permeability is an important transport property of rock material,which directly reflects the ability of rock material to flow through the fluid.The study of rock permeability plays an important role in the exploitation of oil and gas reservoir,the exploitation of groundwater resources and the stability of engineering rock mass.The study of rock permeability is mainly based on experiments.At present,the measurement technology of rock permeability under the condition of normal temperature and three axial stress is relatively mature.Laboratory Determination of rock permeability under the temperature,although the test study has been carried out a large number of however,high temperature determination of rock permeability is still under study,the relationship between temperature and permeability of rock are still controversial.Therefore,the study on the permeability of the high temperature rock mass is not deep,and is only limited to the empirical formula based on the theory or the statistical law.The high temperature developed by Taiyuan University of Technology,the three axle test machine,high temperature simulation using real-time heating mode(100?~400?)three axial stress state of limestone and sandstone permeability in different temperature ranges were determined by on-line gas method,and analyzed by using the theory of thermal elasticity.The results show that: in the three axial stress state,deformation due to thermal expansion and thermal cracking of the comprehensive effects of limestone and sandstone permeability variation with temperature is nonlinear: in the low temperature section of rock permeability decreases with the increase of the temperature,in the middle temperature stage,rock permeability increases with the temperature.At high temperature,the permeability of rock with the increase of temperature tends to be gentle.The results of this study have important theoretical value for the geothermal exploitation of high temperature rock mass and the safe disposal of nuclear waste.