煤层中水-气两相流体渗透性影响因素分析

煤层气储层的渗透性是反映煤层中气、水等流体的渗透性能的重要参数,决定着煤层气的运移和生产。应用煤岩学的方法,从原地应力、有效应力,煤层埋藏深度与原始储层压力,天然裂隙和压力变化等几个方面,对影响煤层渗透率的因素进行了分析、探讨,得出了煤层渗透率与原地应力、有效应力存在相关性,渗透率随煤层埋藏深度的增大而减小、随原始储层压力增大而降低,天然裂隙发育有利于提高渗透性,在开采中受克林肯伯格效应、基质收缩及有效应力影响的结论,为预测煤层气储层的渗透性提供了依据。

Analysis on the Factors Affecting the Permeability of Double-Phase Liquid of Water and Gas in Coal Seam

The permeability of coal-bed methane reservoirs is the key parameter which reflects the permeation performances of the fluids(gas and water etc.) in the coal seam and decides the migration and production of the coal-bed methane.From in-situ stress,effective stress,embedding depth of coal seam and pressure in original reservoirs,natural fracture and the variations of pressure,the paper analyses discusses the factors affecting permeability rate of coal seam by using the theory of coal petrology,and draws conclusions that there are relativity between the permeability of coal seam and in-situ stress,effective stress,the permeability of coal seam reduces with the increasing of embedding depth of coal seam and the increasing of pressure in original reservoirs,the developed natural fracture is advantageous to increasing the permeability,and the permeability of coal seam is influenced by Klinkenberg effect,substrate shrinking and effective stress during exploiting coal seam.This provides scientific basis for forecasting the permeability of coal-bed methane reservoirs.