低渗煤层大直径钻孔瓦斯抽采参数优化研究  

Research on Optimization of Extraction Parameters of Large Diameter Drilling in Low Permeability Coal Seam for Methane Drainage

作　　者：张文豪 崔崇斌 张智[3] 魏明尧[4] 马晓 ZHANG Wenhao;CUI Chongbin;ZHANG Zhi;WEI Mingyao;MA Xiao(Xishan Coal and Electricity Group Co.,Ltd.,Taiyuan 030053,China;Malan Coal Mine,Shanxi Xishan Coal and Electricity Group Co.,Ltd.,Gujiao 030200,China;National Engineering Research Center for Coal Gas Control,Huainan 232001,China;IOT Perception Mine Research Center,China University of Mining and Technology,Xuzhou 221008,China)

机构地区：[1]西山煤电(集团)有限责任公司,太原030053 [2]山西西山煤电股份有限公司马兰矿,山西古交030200 [3]煤矿瓦斯治理国家工程研究中心,安徽淮南232001 [4]中国矿业大学物联网(感知矿山)研究中心,江苏徐州221008

出　　处：《煤炭技术》2024年第2期195-199,共5页Coal Technology

摘　　要：针对低渗煤层瓦斯抽采存在预抽难度大的问题,提出大直径钻孔预抽能够降低低渗煤层瓦斯含量的方法。但由于低渗煤层对气固耦合效应影响敏感,抽采中渗透率变化过程不明确,导致大直径钻孔抽采参数设计依据不足。首先分析了低渗煤体渗透率演化的主控因素,建立了煤层瓦斯运移理论模型,模拟研究了大直径钻孔不同工况下对低渗煤体的瓦斯抽采效果,对比分析不同孔径、负压、孔间距下煤层瓦斯渗流规律。结果表明钻孔孔径越大造成的煤体卸压区越大,瓦斯抽采量越高,瓦斯残余含量也越小,但抽采效果增加幅度逐渐降低。负压越大瓦斯抽采量越大,但差别较小,因此负压对提升抽采效率影响较小。受渗透率演化的影响,不同钻孔间距下瓦斯抽采总量差别较大,在间距为3 m时,40~120 d阶段内抽采量最高,后期抽采量缓慢下降。间距5 m时抽采总量最高,抽采范围内的瓦斯残余含量降低较多。现场优化抽采后的瓦斯抽采纯量与模拟结果一致,表明了研究结论可靠。该研究结果可为煤矿井下大直径钻孔瓦斯抽采参数设计提供理论依据与应用参考。Considering the challenging problem of methane extraction in low permeability coal seams,large diameter borehole is used to prevent gas disaster during pre-pumped stage.The gas drainage effect of low permeability coal seam under different working conditions with large diameter borehole was studied employing the numerical simulation method.The gas pressure,total amount of extraction and residual gas content were analyzed as the reference to conclude the gas drainage effect.Comparing and analyzing the data of coal seam per-gas extraction under different pore sizes,different negative pressures and different hole spacing,the law of gas seepage under large diameter borehole was obtained.The results show that the size of the borehole affects the distribution of coal pressure relief damage,and the larger the pore size,the larger the coal pressure relief zone.The higher the amount of gas extracted,the smaller the residual gas content,however,the increase in extraction effect decreases.The larger the negative pressure,the greater the gas extraction capacity,however the difference is small,therefore the negative pressure has less effect on improving the pumping efficiency.The total amount of gas extracted at different drill spacings varies greatly.At a spacing of 3 m,the 40-120 day stage sampling is the highest,however the later sampling volume slowly decreases.At a spacing of 5 m,the total amount of extraction is the highest,and the residual gas content in the extraction range is much reduced.The purity of gas extraction after the optimized field extraction is consistent with the simulation results,indicating that the research conclusion is reliable.The results of this study can provide a theoretical basis and application reference for the design of gas extraction parameters for large diameter borehole in coal mines.

关 键 词：瓦斯抽采 低透气性煤层 大直径钻孔 数值模拟 

分 类 号：TD712[矿业工程—矿井通风与安全]