Dynamic changes laws of the coal reservoirs permeability under the superimposition of multi influential factors
Abstract：The primary influential factors of coal reservoirs permeability were analyzed, and the basic theoretic prob- lems about viscid seepage of coal reservoirs were discussed. In different conditions of axial compression, confining pres- sure and pressure gradient of gas, the seepage CH4 experiments of some anthracite samples, which were picked from Jincheng mining area, Shanxi Province, were carried out in three-dimensional stress field. It was calculated and ana- lyzed the factors of effective stress, coal matrix shrinkage and slippage effect of gas affect permeability, and how the ac- tions of superimposition behave. It is considered that the boundary layer consists of molecules of CH4 in adsorption state when gas permeating in pore-fissure of coal reservoirs. The slippage effect occurs out of the boundary layer. The dynamic changes of the coal reservoirs permeability are the superimposition of such influential factors as effective stress, coal matrix shrinkage and slippage effect. The permeability attenuates observably as the pressure gradient from 0 to 0. 1 MPa. The magnitude of contribution what slippage effect does for permeability is far less than coal matrix shrinkage effect. The effect of slippage may be ignored when pressure gradient increases.
Keywords：coal reservoirspermeabilitysuperimpositioninfluential factorviscid seepage
Publication Date：2012-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 1348-1353 )