Evolution law of coal seam permeability in CO2-ECBM process
XUE Ensi
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.
Keywords：coalbed methanegas extractionpermeabilityCO2-ECBMmulti-physics field coupling
Publication Date：2024-04-20
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 42-47 )