Study on gas emission effect of coal seam borehole under high temperature field

Abstract

Aiming at the difficult problem of gas drainage in low permeability outburst coal seam in China, taking the transportation lane of coal mining face in K15 coal seam of Maizigou Coal Mine in Guizhou Province as the engineering background, through the establishing the multi-field coupling model of gas flow in coal mining face under high temperature field, the gas drainage effect of coal seam boreholes under different heating temperature, borehole diameter and borehole spacing conditions was simulated and studied. The research shows that temperature has a significant impact on the effect of coal seam gas emission. When the heating temperature is 86 ℃, the gas pressure decreases significantly; the borehole diameter has a great influence on the effect of coal seam gas emission. When the borehole diameter is 113 mm, the maximum gas pressure between boreholes is 0.36 MPa, the maximum gas pressure decreases by 14.28% year on year, and the gas emission from boreholes increases by 27.27%. The effect of borehole spacing on coal seam gas pressure and discharge effect is also very obvious. When the borehole spacing is 1 m, the maximum gas pressure between boreholes is 0.45 MPa, and the influence range is 5.72 m. The decrease range of gas pressure increased by 37.8% compared with the hole spacing of 1.5 m and the influence range increased by 18.18% compared with the hole spacing of 1.5 m. The comprehensive gas discharge effect was the best. Comparing the simulation results of different schemes, the numerical simulation scheme 9 has the best gas emission effect.

Keywords

• methane desorption
• gas emission
• enclosed roadway
• high temperature field
• gas disaster