Temperature-stress sensitivity of high-rank coal permeability

Sensitivity of the coal reservoir permeability to temperature and stress is one of the basic parameters for evaluating the physical properties of deep coal reservoir. Using the heating and overburden pressure permeability-porosity tester,the permeability and porosity of the anthracite samples from the Chengzhuang,Jincheng,Shanxi,were measured.Combining with the pore structure and other data,the sensitivity of high rank coal to temperature and pressure was discussed. It is show that the porosity and permeability of high-rank coal is negatively correlated to the pressure in a power function,reduce rapidly as the pressure rises when pressure is lower,and tend to be stable in higher pressure phase.High-rank coal permeability is not sensitive to temperature,decreases with the increase of temperature when the pressure is less than 2 MPa,and has not significant correlation with temperature once the pressure is higher than 2 MPa.Therefore,the pressure is a major effect factor to the porosity and permeability of high-rank coal,and the temperature has less influence on the porosity and permeability. Based on curvature analysis method,stress sentivity of permeability of high rank coal of Chengzhuang Mine pressure sensitivity was analyzed. Compared with Zhengzhuang and Hancheng high rank coal,Chengzhuang coal has stronger stress sensitivity in low pressure stage. Therefore,resonable pumpingsysten of coalbed methane development in Chengzhuang Mine should be made to avoid negative effect due to stress sensitivity of permeability.