花眼护孔管对顺层钻孔瓦斯抽采效果的影响研究

Influence study of pipes with many small holes on gas drainage by bedding boreholes

为探究顺层钻孔内花眼护孔管对瓦斯抽采的作用程度,建立基于裂隙-孔隙双重介质的煤岩瓦斯气-固耦合数学模型,分别对顺层钻孔内花眼护孔管不同长度的布置方式进行瓦斯抽采数值模拟;此外,在潘三煤矿11-2煤层开展现场试验,对比分析钻孔内布置与不布置花眼护孔管的实际抽采效果。结果表明:当顺层钻孔全程使用花眼管护孔时,模拟得到的钻孔周围残余瓦斯压力和含量最低;使用花眼护孔管的钻孔周围瓦斯含量明显下降,并且随着抽采时间的增加,花眼护孔管对瓦斯抽采的促进效果更加显著。

For the sake of exploring the degree of influence of pipes with many small holes on the gas drainage by bedding boreholes,a gas-solid coupling model of coal seam was established on the basis of the fracture-pore dual media and gas drainage numerical simulation of pipes with many small holes in different layouts along coal seam was carried out.Besides,field experiment was conducted in the 11-2 coal seam of Pansan Coal Mine,and the actual gas drainage effects of cases having or not pipes with small holes in the boreholes was compared and analyzed.The results show that the application of pipes with many holes leads to the lowest residual gas pressure and content around the borehole,with the significant decrease of gas content around the borehole,the influence of pipes with small holes on gas drainage will be further enhanced with the increase of extraction time.