Numerical Simulation of Gas Drainage in Low-Permeability Fissured Coal

Abstract

A dynamic model which can use a large pressure to simulate two-dimensional gas drainage in low-permeability fissured coal is constructed based on Lattice Boltzmann Method (LBM), a numerical program and a software system to simulate the distribution rule of gas pressure and flow mark were developed, and the gas drainage ratio which can determine the gas drainage effect is calculated by statistical method. The simulation results demonstrate that the gas flows is laminar flow far away from drainage pore at the beginning of gas drainage. When the gas seepage achieves balance state after some time, the whole gas seepage field flows except near drainage pore is laminar flow. With the increment of the drainage pore diameter, the drainage ratio turns higher and the variety ratio of drainage ratio falls. When the drainage ratio reaches some range, extending pore diameter have few effects on drainage ratio.