煤体钻孔瓦斯有效抽采半径判定技术

Technology for determining effective drainage radius of coal seam drill hole

为研究瓦斯矿井本煤层准确测定瓦斯有效抽采半径问题,提出了利用吨煤瓦斯抽采量计算钻孔瓦斯有效抽采半径的测定方法.基于瓦斯钻孔衰减负指数规律建立钻孔瓦斯抽采模型,解算出吨煤瓦斯抽采量,并与其煤层原始瓦斯含量对比,得出煤层残存瓦斯含量Wc和抽采率η,以此判断钻孔瓦斯有效抽采半径,只有同时满足{Wc≤8m3/t∩η≥30%},才为钻孔瓦斯有效抽采半径.研究结果表明:随着预抽时间延长,钻孔瓦斯有效抽采半径逐渐增大,直至极限抽采半径.通过工程实践,分析了不同时间的有效抽采半径,为瓦斯矿井抽采工作提供了可靠的抽采参数,具有实际应用价值.

In order to measure the effective drainage radius of mining-coal bed accurately in low gas mine, a measure method which is based on gas drainage volume of ton coal is proposed. Based on the gas drainage negative exponential decay regularity, a gas drainage model is established. Then the ton coal gas drainage volume is calculated, and compared with the original gas content in coal seam, thus obtain residual gas quantity （wo） and drainage efficiency （η）, which is used to judge the effective drainage radius ofborehole, only satisfying condition of {We ≤ 8m^3/t∩η≥ 30%}, effective drainage radius could be determined. The result shows that the effective drainage radius is increased as pre-drainage time prolonged, until limit. The drainage radius in different time was analyzed in coal mine, which provides accurate drainage parameters for gas drainage effectively, and the conclusion has practical application value.