Permeability dynamic variation features of coal reservoir in exploitation process of Fanzhuang Block

In order to ascertain the permeability dynamic variation features of the coal reservoir in the development process of the coalbed methane as well as the coupling relationship the permeability and production capacity, based on revealing the dynamic variation mechanism of the permeability rate in the coal reservoir in the development process and the derivation of the permeability rate calculation method, in combination with the development practices on the coalbed methane in Fanzhua ng Block at the south part of Qinshui Basin, the paper had an inversion on the dynamic variation features of the coal reservoir permeability rate in the different develop ment well area and different capacity type well development process. The study showed that the porosity-permeability rate model established could be applied to effecti vely invert the dynamic variation of the permeability rate in the development of the coalbed methane. During the development process, the damage rate of the dynamic permeability rate in the coal reservoir would be jointly restricted by stress sensitivity and matrix shrinkage effect and would have a close relationship to reservoir pressu re, gas content and in-situ permeability. A coordinative and benign development between the permeability and the gas production capacity of the coal reservoir would b e the key to realize the high production and the stable production and the slow and continuous drainage, proper high reservoir pressure, high gas content and high in-si tu permeability rate would be important factors to ensure the rebound phenomenon of permeability occurred in the late of reservoir.