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针对豫西“三软”煤矿区瓦斯低渗难抽问题的特殊性,探讨了主采二1煤层生、储气层的变形特征。以ABAQUS软件为平台,依托告成煤矿建立了滑动构造带三维非线性流—固耦合水力压裂模型。应用多参数耦合模拟方法,探讨了定向注水压裂过程中目标层的流变—损伤—渗流耦合行为;同时利用T—P损伤演化准则的Cohesive单元,模拟了目标层裂隙的起裂和扩展过程。此外,探讨了煤岩体对动力荷载的响应机制和动态条件下的压裂效果。研究结果表明,定向注水新工艺条件下,当注水压力为4.5MPa,注水时间在2h左右时,水力压裂在顺层软煤中的影响半径基本可以达到80~100m这一理想数据,从而大幅度地改善了“三软”煤层低渗性能。实践证明,采用正确的施工方法和技术参数优化组合,可以有效提高煤层的透气性和瓦斯抽采效果,对复杂矿区瓦斯综合利用具有重要借鉴意义。
Aiming at the peculiarity of the gas drainage problem in the west of Henan Province, this paper discusses the deformation characteristics of the raw coal and gas reservoirs in the main mining area. With ABAQUS software as a platform, a three-dimensional nonlinear flow-solid coupling hydraulic fracturing model of sliding structure zone was established based on the coal mine of Chengcheng. The multi-parameter coupling simulation method was used to investigate the rheological-damage-seepage coupling behavior of the target layer during directional waterflooding. At the same time, the Cohesive element of the T-P damage evolution criterion was used to simulate the initiation and propagation of the target fracture . In addition, the response mechanism of coal and rock mass to dynamic load and the fracturing effect under dynamic conditions are discussed. The results show that when the water injection pressure is 4.5MPa and the water injection time is about 2h under the new condition of directional water injection, the radius of influence of hydraulic fracturing in soft bedding coal can basically reach the ideal data of 80 ~ 100m, Amplitude to improve the “three soft ” low permeability coal seam performance. Practice has proved that using the correct combination of construction methods and technical parameters, can effectively improve the permeability and gas drainage effect of coal seams, comprehensive utilization of complex mines has important reference significance.