The numerical simulation for seepage rule of coal-bed methane with hydraulic cutting seam mining based on Matlab

摘要

It's an effective ways to hydraulic-cutting seam for drainage that solves gas disaster and prevents impact pressure in mining. In order to get the seepage rule and productivity prediction of hydraulic-cutting for coal-bed methane(CBM) mining, the theory of seepage mechanics combined with elastic-plastic mechanics was used to set up a mathematical model and the boundary conditions and initial conditions was given meanwhile. The Matlab software was used to obtain the variation rule of coal-bed stress field, gas pressure field and gas extraction yield. The simulation results show that the effective stress is released after hydraulic-cutting seam used and the effect of unload is obvious along seam; the numbers of crack and fracture increases and the length and width of crack and fracture improve. So the permeability of coal seam enhanced and the absorbed gas disorpted greatly from coal seam because of the increase of contact area. The extraction yield of gas is bigger to hydraulic-cutting seam than conventional drilling. The simulation results show the advantage of hydraulic-cutting seam for CBM extraction and the method of simulation is significant to the execution project and productivity prediction of hydraulic-cutting seam for CBM industrial production increasing technology.