PetroChina Huabei Oilfield Company School of Energy, China University of Geosciences (Beijing)

为了查明煤层气开发过程中煤储层渗透率动态变化特征及其与产能的耦合关系,在揭示开发过程中煤储层渗透率动态变化机理,推导渗透率计算方法基础上,结合沁水盆地南部樊庄区块煤层气井开发实际,反演了不同开发井区、不同产能类型井开发过程中煤储层渗透率的动态变化特征。研究表明:建立的孔隙度-渗透率模型可以有效反演煤层气开发过程中的渗透率动态变化。开发过程中煤储层动态渗透率伤害率受应力敏感和基质收缩效应共同制约,与储层压力、含气量和原始渗透率关系密切。煤储层渗透性和产气能力的协同良性发展是实现高产稳产的关键,缓慢连续的排采、适中的高储层压力、高含气量和较高的原始渗透率是保证储层后期渗透率出现反弹现象的重要因素。

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.