摘要
Abstract
In order to study the spatio-temporal evolution law of coal seam permeability in the process of CO2-ECBM,a CO2-ECBM fluid-solid-thermal multi-field coupling numerical model is established by using COMSOL Multiphysics numerical simulation meth-od based on the geological conditions of Liliu Mining Area as the engineering background.The CO2-ECBM process is numerically simulated by five-point well layout method,and the spatio-temporal evolution of coal permeability with CO2 injection is discussed.The results show that gas pressure,CO2 injection and shrinkage/expansion deformation of coal matrix are the key factors affecting permeability evolution.After the adsorption of CO2,the expansion deformation of coal matrix plays a leading role,occupying the pore space,resulting in the decrease of permeability,the mean permeability in the range affected by CO2 decreased by 40%.Along the CO2 injection well to the extraction well,the permeability is less and less affected by CO2,it shows a monotonic upward trend.The mean permeability increased by 14%outside the influence range of CO2.关键词
煤层瓦斯/瓦斯抽采/渗透率/CO2-ECBM/多物理场耦合Key words
coalbed methane/gas extraction/permeability/CO2-ECBM/multi-physics field coupling分类
矿业与冶金
