松软煤层可控冲击波增透瓦斯抽采创新实践——以贵州水城矿区中井煤矿为例  

Innovative engineering practice of soft coal seam permeability enhancement by controllable shock wave for mine gas extraction:A case of Zhongjing Mine, Shuicheng,Guizhou Province,China

作　　者：张永民[1] 蒙祖智 秦勇[3] 张志峰 赵有志 邱爱慈[1] ZHANG Yongmin;MENG Zuzhi;QIN Yong;ZHANG Zhifeng;ZHAO Youzhi;QIU Aici(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China;Guizhou Shuicheng Mining Co.Ltd.,Liupanshui 553000,China;Key Laboratory of CBM Resources and Reservoiring Process,Ministry of Education,China University of Mining and Technology,Xuzhou 221008,China;Ningxia Coalfield Geological Survey,Yinchuan 750002,China)

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,陕西西安710049 [2]贵州水矿控股集团有限责任公司,贵州六盘水553000 [3]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221008 [4]宁夏煤田地质局,宁夏银川750002

出　　处：《煤炭学报》2019年第8期2388-2400,共13页Journal of China Coal Society

基　　金：国家自然科学基金重点资助项目(U13612031);国家科技支撑计划资助项目(2012BAK04B02);国家重点研发计划资助项目(2018YFC0808002)

摘　　要：松软煤层瓦斯低成本高效抽采属于世界性技术难题之一,中井煤矿回采工作面规模煤层可控冲击波增透效果为解决这一难题提供了一个成功示范。通过可控冲击波增透煤层钻孔,单孔日均瓦斯抽采量平均提高3.37倍,最高达到6.54倍,瓦斯浓度平均提高2.31倍,增透有效半径可达40~60m,将原来的难以抽采煤层转变为可以抽采~容易抽采煤层,需要的钻孔工程量只有传统抽采工程的11%~18%。在钻孔直径、冲击能量条件相同条件下,示范区煤层增透的最佳冲击密度在1.0~1.1次/m,增透段长度应大于120m;在最佳冲击密度条件下,回采工作面抽采孔增透效果主要与抽采开始时机、周围抽采环境有关,巷道掘进暴露越晚以及回采工作面增透孔相互干扰越明显,抽采效果越好。与传统钻孔抽采流量幂指数单调衰减曲线形态不同,增透孔瓦斯流量曲线表现为“两段式”变化的典型特征,其中多数孔第1阶段流量曲线出现类似于煤层气地面井排水降压的流量“峰”,第2阶段流量衰减系数也远远小于对比基准。分析认为,产生上述效果的机理在于两个方面:①以冲击波增透孔为中心向外,煤层流场由井巷采动流场向冲击波改造流场过渡,大大扩展了原有的有效流场半径,冲击波改造流场类似于地面井煤层流场,可以通过排水降压形式产出煤层瓦斯;②冲击波改造流场为抽采影响带流场提供了更为充足的瓦斯气源,有效阻滞了瓦斯流量衰减系数的快速降低,显著提高了抽采效果。Low cost and high efficiency gas extraction from soft coal seam is one of the worldwide technical problems.The effect of controlled shock wave (CSW) permeability enhancement of coal seam in Zhongjing coal mine provides a successful demonstration to solve this problem.Through the CSW permeability enhancement of coal seam in borehole,the average daily gas extraction volume of single borehole is increased by 3.37 times,with the maximum of 6.54 times,the methane concentration is increased by 2.31 times,and the effective radius of CSW operation is up to 40- 60 m .The original difficult-to-extract coal seam is transformed into easy-to-extract coal seam,and the required borehole engineering work is only 11%-18% of the traditional borehole engineering work.When borehole diameter and impact energy are the same,the optimum CWS density of permeability enhancement in the demonstration project should be between 1.0 and 1.1 times/m,and the length of CSW operation section should be more than 120 m.Under the optimum CSW density condition,the enhanced-permeability effect of extraction hole in the mining face is mainly related to the starting time of extraction and extraction environment around a borehole.The later the exposure of excavation along coal seam roadway and the more obvious the mutual interference of CSW boreholes in mining face,the better the extraction effect.Comparing with the gas flow curve pattern from a traditional borehole with the monotonous attenuation of power exponent,the gas flow curve from a CSW borehole occurs in a “two-stage” pattern,in which the flow curve of most boreholes in first stage has a flow “peak” similar to that of surface CBM well for drainage and depressurization,and the flow attenuation coefficient in second stage is much smaller than that of the comparison benchmark.It is suggested that the mechanism of above effects lies in two aspects.Firstly,taking a CSW borehole as the center and outward,the flow field in coal seam transits from mining flow field to CWS flow field,which greatly

关 键 词：可控冲击波 松软煤层 瓦斯抽采 增效机理 水城矿区 

分 类 号：TD712[矿业工程—矿井通风与安全]