高煤级煤储层渗透率在煤层气排采中的动态变化数值模拟

针对高煤级煤储层渗透率尤其是其动态变化规律极少开展研究的现状，基于现代测试技术和沁水盆地排采效果较好的煤层气井实测排采数据，利用目前国际上较为先进的煤层气数值模拟软件CINET2，采用分段拟合的方法对煤层气井的产气、产水过程进行历史拟合和修正，进而对高煤级煤储层渗透率在开采中的动态变化规律进行了探讨．研究结果表明，煤层气并工作制度的变化会引起煤层气井采动状况发生变化，导致煤储层渗透率产生波动．煤储层渗透率随着煤层气井排采时间呈指数规律缓慢衰减，与物理模拟实验结果显示的渗透率与有效应力的关系具有相似的结论．

Numerical Simulation on Dynamic Variation of the Permeability of High Rank Coal Reservoirs during Gas Recovery

Aim at the present condition that the permeability of high rank coal reservoirs and its dynamic change regulation have been rarely studied,based on the modern testing technologies and actual measure data of Coalbed methane(CBM) well with better drainage effect in Qinshui Basin,using the international advanced CBM well numerical simulation software(COMET2),the dynamic change regulation of the permeability of high rank coal reservoirs during gas recovery has been discussed,using the gas and water recovery process in divided stage is matched.The result shows that the recovery condition of the CBM well will change with the change of the recovery system,and the permeability of coal reservoirs will also change.The permeability of high rank coal reservoirs tends to decline in exponent gradually,which is similar to the relationship between the permeability and effective stress obtained by physical simulation.