糯东矿水力冲孔增透机理及效果评价方法研究

发布时间：2018-04-11 12:21

  本文选题：松软高突煤层 + 瓦斯抽采　； 参考：《北京科技大学》2017年博士论文

【摘要】：水力冲孔是提高矿井瓦斯抽采效果的关键技术之一。本文通过理论分析,构建了水力冲孔瓦斯增透理论模型,揭示了水力冲孔卸压增透机理。运用COMSOL Multiphysics软件对松软高突煤层水力冲孔效果进行了数值模拟,并基于电法响应实验平台,构建了水力冲孔评价系统,提出了效果评价指标,且进行了现场验证。具体如下:基于Hoek-Brown破坏准则,分析了钻孔周围煤体力学性能,得出了冲孔后钻孔卸压区的变化规律;分析了水力冲孔裂缝生成、发育及扩展过程,推导得出了裂缝扩展长度计算方程。结合质量守恒方程、朗格缪尔方程及达西定律,建立了含瓦斯煤体渗流方程,并考虑到孔隙率和渗透率的动态变化,构建了钻孔抽采瓦斯流固耦合模型。依据上述理论模型,应用COMSOLMultiphysics软件,对糯东煤矿水力冲孔卸压增透效果进行了数值模拟,得出了糯东煤矿水力冲孔冲出煤量1t/m、每排6孔、间距8.48m的布孔方案。为评价布孔方案现场应用效果,基于直流电法响应,开发了水力冲孔实验室模拟系统,通过实验室实验,分析了载荷、水、裂隙对煤岩体视电阻率的影响,揭示了煤岩体在冲孔过程中视电阻率的变化规律。提出以视电阻率平均变化系数I作为水力冲孔抽采瓦斯效果评价指标,制定了水力冲孔效果评价分级标准。根据上述研究结果,对糯东煤矿17号煤层进行了现场冲孔,并运用直流电法对冲孔区域进行了效果评价。结果表明,水力冲孔的有效影响范围为:在深度上集中在-25m～-45m,在走向上集中在35m～75m,走向影响半径约20m。测试区域视电阻率平均变化系数I=93%,水力化措施评价等级为Ⅱ级,证明该区域水力冲孔卸压增透瓦斯效果显著。研究成果对松软高突矿井的煤与瓦斯突出治理工作具有借鉴和参考意义,同时为全面有效评价瓦斯治理效果提供了科学依据和理论指导。
[Abstract]:Hydraulic punching is one of the key techniques to improve the effect of gas drainage.Based on the theoretical analysis, a theoretical model of hydraulic punching gas antitransmittance is constructed, and the mechanism of hydraulic punching pressure relief is revealed.The hydraulic punching effect of soft high outburst coal seam was simulated by COMSOL Multiphysics software. Based on the experimental platform of electric method response, the evaluation system of hydraulic punching was constructed, and the evaluation index was put forward, and the field verification was carried out.The main contents are as follows: based on the Hoek-Brown failure criterion, the mechanical properties of coal body around the borehole are analyzed, and the variation law of the pressure relief zone of the borehole after punching is obtained, and the process of formation, development and expansion of the cracks in hydraulic punching hole is analyzed.The calculation equation of crack propagation length is derived.Combined with mass conservation equation, Langmuir equation and Darcy's law, the seepage equation of gas-bearing coal body was established, and considering the dynamic change of porosity and permeability, the fluid-solid coupling model of gas extraction by borehole was constructed.According to the above theoretical model and using COMSOLMultiphysics software, the antireflection effect of hydraulic punching holes in Naodong Coal Mine is simulated, and the hydraulic punching capacity of 1 t / m, 6 holes per row, and the spacing of 8.48 m are obtained.In order to evaluate the field application effect of the hole layout scheme, a hydraulic punching laboratory simulation system was developed based on the response of DC method. The effects of load, water and fracture on apparent resistivity of coal and rock mass were analyzed through laboratory experiments.The change law of apparent resistivity of coal and rock mass during punching is revealed.The average change coefficient of apparent resistivity (I) is used as the evaluation index of gas extraction effect of hydraulic punching hole, and the grading standard for evaluation of hydraulic punching effect is established.According to the above research results, the No. 17 coal seam of Naodong Coal Mine was punched on the spot, and the effect of punching area was evaluated by using direct current method.The results show that the effective influence ranges of hydraulic punching are as follows: the depth is -25m ~ 45m, the strike direction is 35m ~ 75m, and the strike radius is about 20m.The average coefficient of change of apparent resistivity in the test area is I _ (93), and the evaluation grade of hydraulic measures is grade 鈪，

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