钻孔数量对瓦斯抽采量及抽采时间的影响

Effect of borehole amounts on gas drainage quantity and drainage time

基于自主研发的多场耦合煤层气开采物理模拟试验系统升级改造了顺层钻孔瓦斯抽采系统,开展了不同钻孔数量条件下顺层钻孔瓦斯抽采物理模拟试验,探讨了瓦斯抽采量(瞬时流量、累积流量)和抽采时间的演化规律.结果表明:当钻孔数量由1个增加到2,3和4个时,单钻孔累积流量约下降至原来的0.60,0.45和0.35倍.不同钻孔数量抽采时,瞬时流量曲线出现交叉现象,即抽采前期钻孔数量越多瞬时流量越大,中后期逐渐变化为钻孔数量越多瞬时流量越小.累积流量随钻孔数量的增加呈对数函数增加,钻孔数量越多,其增加效果越不明显.抽采时间随钻孔数量的增加呈幂函数降低,钻孔数量越多,其下降效果越不明显.

The gas drainage system with bedding boreholes was upgraded based on the self-developed multi-field coupling test system,and the physical simulations of bedding borehole drainage with different borehole amounts were conducted.The gas flow rate and cumulative flow rate were analyzed.The results show that the cumulative flow rate of the same branch borehole falls 0.60times,0.45times and 0.35times when the borehole amounts increase from 1to 2,3and 4.The crossover of flow rate curves with different borehole amounts occurs during gas drainage,namely the greater the borehole amounts,the bigger the flow rate in the early stage of gas drainage.While in the later stage,the greater the borehole amounts,the smaller the flow rate.The cumulative flow rate increases with borehole amounts which obeys logarithmic law,and the effect drops with the increasing of borehole amounts.The drainage time decreases with borehole amount which obeys power function,and the declining effect decreases with the increasing of borehole amount.