Study on time-space evolution law of gas drainage with drilling along coal seam

doi:10.13199/j.cnki.cst.2017.02.014

Abstract：In order to study the relationship between the gas drainage effect with drilling along coal seam and the drainage radius as well as the drainage time,based on the seepage theory,gas state equation and gas content calculation equation,a mathematical model of the timespace evolution law for the gas drainage in the mining seam was established.With the application of Comsol numerical simulation,based on the engineering background of No.1320 1 1 coal mining face in Zhongheng Mine,the gas pressure distribution within the radial scope of a single borehole under the different drainage time was obtained,a dynamic variation relationship between the drainage radius and the drainage time was analyzed and the logarithm function relationship of the time-space evolution in the process of the gas drainage was further derived.The comparison experiments of the borehole gas drainage under the condition of different drainage radius were conducted.The function relationship rationality and accuracy on the space and time evolution law of the gas drainage when the drainage radius less than 2 m or the drainage time within 180 days was calculated and verified.The function relationship conforms actual extraction law.