顺层平行钻孔预抽回采区域煤层瓦斯数值模拟

Numerical Simulation of Gas Pre-drainage from Mining Area by Parallel Holes Drilled along Coal Seam

为了得到采取顺层长钻孔措施和顺层交错钻孔措施的瓦斯抽放效果,建立了顺层平行钻孔预抽煤层瓦斯数学模型,并采用有限体积法模拟计算出不同时刻钻孔周围煤体瓦斯压力分布与钻孔累计抽放瓦斯量。模拟结果表明,合理的顺层单向钻孔和顺层交错钻孔布置,对于预抽回采区域煤层瓦斯均取得良好效果;顺层钻孔抽放瓦斯效果与煤层渗透率、煤层原始瓦斯压力及煤层钻孔布置密切相关。

In order to obtain the gas drainage effect by both long and short staggered parallel boreholes along the coal seam,a mathematical model for gas drainage by parallel boreholes drilled along the coal seam was established and the finite volume method was applied to simulate the gas pressure distribution in coal body around the borehole and the accumulative gas drainage quantity per borehole at different time. The simulated results showed that the reasonable arrangement of both long and short staggered boreholes along the seam achieved good drainage effect; the gas drainage effect by the boreholes along the seam was closely related to the gas permeability and the original gas pressure of the coal seam and the borehole arrangement in the coal seam.