近距离煤层群定向长钻孔拦截卸压瓦斯抽采技术研究与实践

Research and practice on pressure relief gas extraction technology of directional long borehole interception in near coal seam group

突出煤层的灾害治理和瓦斯抽采一直是困绕煤矿安全及高效生产的技术性难题。目前,突出煤层瓦斯治理多以开采保护层和钻孔预抽为主,但存在成本高、效果差的问题。平顶山矿区属于典型的多煤层近距离开采煤田,所采用区域治理措施多为开采保护层,存在开采层与被保护层受采动影响地应力相互传导激烈、回采期间瓦斯涌出量大的难题。针对这一问题,平煤四矿利用定向钻进技术能够实现钻孔轨迹精确可控、目标位置探测精准、抽采服务时间长等优点,在保护层工作面试验研究了煤层顶(底)板钻孔顺向梳状布置以钻代巷和岩层间拦截卸压瓦斯抽采技术,并通过钻孔全程下筛管、孔内进气循环排水等管理措施,使顶(底)板定向钻孔单孔瓦斯抽采纯量长期保持在1.5 m^(3)/min和5.0 m^(3)/min,达到了高效抽采的目的,为多煤层突出矿井保护层开采条件下的全钻孔瓦斯治理探索了新途径。

The disaster management and gas extraction of outburst coal seams have always been a technical challenge that hinders the safety and efficient production of coal mines.At present,the gas control of outburst coal seam is mainly by mining protective layer and drilling pre-drainage,but there are problems of high cost and poor effect.Pingdingshan mining area is a typical multi-coal seam short-distance mining coal field,and the regional control measures adopted are mostly mining protection layer.This control route has the problems of intense mutual transmission between mining layer and protected layer and large gas emission during mining.In view of this problem,the No.4 mine of Pingmei Coal mine can realize the advantages of precise and controllable drilling track,accurate detection of target position and long extraction service time by using directional drilling technology.In the working face of the protective layer,the comb shaped arrangement of the top(bottom)plate boreholes in the coal seam is tested to replace the roadway with drilling and the pressure relief gas drainage technology between the rock strata is intercepted.Through the management measures such as the whole process of the drilling,the air inlet and circulating drainage in the hole,the pure amount of gas drainage in the single hole of the top(bottom)plate Directional drilling is kept at 1.5 m^(3)/min and 5.0 m^(3)/min for a long time,and the purpose of efficient gas drainage is achieved,a new approach has been explored for the full borehole gas control under the conditions of mining the protective layer of multi seam outburst mines.