3D-finite element model for hydrodynamic action on a multilayer coal seam with fluidization zone

Abstract

The paper suggests a mathematical model for the process of hydrodynamic action on a multi-layer coal seam with fluidization zone for methane extraction. Degasification of fluidization zones in coal seams is extremely important because of abnormally increased methane concentration in these zones. The model is formulated as a three-dimensional problem of transient fluid filtration in porous medium with nonlinear fluid pressure dependences for the filtration coefficients for coal and fluidization zone. A filtration-temperature analogy permits to solve the initial boundary-value problem obtained as a problem of thermal conductivity. Finite element approximation of the problem is presented. The computations are carried out using finite element method with the help of thermal analysis module of ANSYS finite element package. The results of the computations enable to determine the size of degassing zone for the coal seam and fluidization zone.