煤层瓦斯抽采单双排钻孔最优布孔研究与应用

Research and Application of Optimal Hole Arrangement for Single and Double Row Drilling in Coal Seam Gas Extraction

为减少定向长距离钻孔的打孔数量,保证瓦斯有效抽采的同时提高整体施工效率,以沙曲二号煤矿九采区为工程背景,建立基于达西定律的流固耦合模型,应用数值模拟软件,分析不同孔间距对于有效消突体积的影响。结果表明:顺层长钻孔合理的布孔方式与数量对煤层抽采效果起重要作用,间距过小会造成资源浪费,间距过大会产生空白抽采区域;单、双排钻孔的最优布孔间距不同,单排钻孔间距在10 m时有最大的瓦斯消突体积,双排钻孔交错排列时,孔间距在13 m时有最大的瓦斯消突体积;双排交错打孔方式,增加孔间距的同时,减少扰动对于周围钻孔的影响,从而降低钻孔失稳概率,钻孔总进尺分别缩短18.18%与33.33%。

In order to reduce the punch hole number of directional long-distance drilling holes,ensure effective gas extraction at the same time,and improve overall construction efficiency,taking the ninth mining area of Shaqu No.2 Coal Mine as the engineering background,a fluid structure coupling model based on Darcy's law is established.Numerical simulation software is applied to analyze the influence of different hole spacings on the effective outburst suppression volume.The results show that a reasonable hole arrangement method and quantity play an important role in the coal seam extraction effect.Too small spacing will lead to a waste of resources,and too much spacing will result in a blank extraction area;The optimal hole arrangement spacing between single and double row drilling holes is different.When the spacing between single row drilling holes is 10 m,there is the maximum gas outburst suppression volume.When the spacing between double row drilling holes is staggered,there is the maximum gas outburst suppression volume when the spacing between boreholes is 13 m;The double row staggered punch hole method increases the spacing between holes while reducing the impact of disturbance on surrounding boreholes,thereby reducing the probability of borehole instability.The total drilling footage is shortened by 18.18%and 33.33%,respectively.