摘要
为实现逆断层瓦斯富集区高效持续抽采,降低煤与瓦斯突出风险,通过综合理论分析、物理相似模拟试验、数值仿真及现场抽采瓦斯工程实践等方式开展地面压裂直井井位优选研究。借助UDEC离散元数值模拟软件,研究上下盘不同开采顺序下煤岩渗透率的演化规律,发现按照上盘—过断层—下盘开采顺序对逆断层区域渗透率的卸压幅度最大,形成了完整的采动裂隙通道,初步确定了井位应布置在逆断层下盘;构建了低渗煤层水力压裂半径反演计算模型,确定地面压裂直井水压裂缝扩展至断面的井位与断层最大间距为150 m;通过物理相似模拟试验与UDEC数值仿真试验,沿工作面走向,研究了逆断层活化状态对井壁稳定性的影响范围,得出地面压裂直井至少与逆断层保持68 m间距才可以保证井壁稳定;通过顶板力学与弹塑性力学理论推导了过断层时井壁可能出现的4种不同形态裂缝的判别公式;沿工作面倾向,开展了“O”形裂隙圈宽度计算,得出地面压裂直井井位与回风巷的水平间距应不超过31.6 m;明确了下盘地面压裂直井井位沿工作面走向与逆断层的间距为68~150 m,沿工作面倾向与回风巷水平间距在31.6 m以内。现场布置压裂直井实施瓦斯抽采,有效降低了逆断层瓦斯富集区煤与瓦斯突出危险性。
To achieve efficient and sustained gas extraction from reverse fault gas enrichment zones and reduce the risk of coal and gas outbursts,a comprehensive study on the optimization of surface fracturing vertical well location was conducted through theoretical analysis,physical similarity simulation experiments,numerical simulation experiments,and on-site gas drainage engineering practice.Using the UDEC discrete element numerical simulation software,numerical calculations were performed to investigate the evolution of coal-rock permeability under different mining sequences of the upper and lower panels.It was found that mining in the sequence of the upper panel,crossing the fault,and then the lower panel results in the maximum pressure relief effect on the permeability in the reverse fault zone,forming a complete mining-induced fracture channel.This finding helps to preliminary establish that the well location should be in the lower panel of the reverse fault.Furthermore,a model for inverting the hydraulic fracturing radius in low-permeability coal seams was constructed.With this model,it was determined that the maximum distance between the location of the surface fracturing vertical well and the fault should be 150 m for effective propagation of hydraulic fractures to the fault.Along the strike of the working face,the influence range of reverse fault activation on wellbore stability was studied through physical similarity simulation experiments and UDEC numerical simulation experiments.A conclusion was drawn that a minimum distance of 68 m should be maintained between the surface fracturing vertical well and the reverse fault in the hope of ensuring wellbore stability.Based on roof mechanics and elasticplastic mechanics theories,discriminant formulas for four different types of fractures that may occur in the wellbore when crossing the fault were derived.Along the dip of the working face,the width of the"O"-shaped fracture zone was calculated.The calculation results unveiled that the horizontal distance between the location of the surface fracturing vertical well and the return airway should not exceed 31.6 m.Additionally,the location of the surface fracturing vertical well in the lower panel should be 68-150 m from the reverse fault along the strike and not more than 31.6 m from the return airway along the dip.The on-site arrangement of fracturing vertical wells for gas extraction diminished the risk of coal and gas outbursts in the reverse fault gas enrichment zone.
作者
秦松
林海飞
唐江波
梁忠秋
杨守国
刘思博
QIN Song;LIN Haifei;TANG Jiangbo;LIANG Zhongqiu;YANG Shouguo;LIU Sibo(College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an,Shaanxi 710054,China;Xishangzhuang Coal Mine,Nanzhuang Coal Group Co Ltd,Yangquan,Shanxi 045000,China;China Coal Technology and Engineering Group Shenyang Research Institute,Fushun,Liaoning 113122,China)
出处
《采矿与安全工程学报》
北大核心
2025年第3期708-719,共12页
Journal of Mining & Safety Engineering
基金
国家杰出青年科学基金项目(52425405)
国家自然科学基金面上项目(52174207)
陕西省杰出青年科学基金项目(2020JC-48)。
关键词
逆断层瓦斯富集区
地面压裂直井
井位
渗透率
水力压裂半径
井壁
reverse fault gas-enriched zone
surface fracturing vertical well
well location
permeability
hydraulic fracturing radius
wellbore
