煤炭工程 ›› 2025, Vol. 57 ›› Issue (6): 106-114.doi: 10. 11799/ ce202506014

• 生产技术 • 上一篇    下一篇

水力冲孔协同注气驱替强化瓦斯抽采技术及应用研究

屈花荣   

  1. 陕西陕煤韩城矿业有限责任公司,陕西 韩城 715400
  • 收稿日期:2024-07-01 修回日期:2024-08-12 出版日期:2025-06-11 发布日期:2025-07-15
  • 通讯作者: 屈花荣 E-mail:894631132@qq.com

Gas extraction enhancement technology with hydraulic flushing and gas-injection displacement

  • Received:2024-07-01 Revised:2024-08-12 Online:2025-06-11 Published:2025-07-15
  • Contact: QU HUARONG E-mail:894631132@qq.com

摘要:

为提高低透煤层水力冲孔钻孔卸压瓦斯抽采效果,消除冲孔诱发的集中应力对瓦斯流动的负效应,提出了水力冲孔协同注气驱替强化瓦斯抽采方法。同时,为探讨影响水力冲孔协同注气驱替增抽瓦斯效果的因素,建立了多组分气体储运过程流-固耦合模型,分析了不同冲孔钻孔等效直径、注气压力和钻孔间距对瓦斯增流和消突效果的影响规律。结果表明:冲孔钻孔等效直径越大,注气初期增流效果越显著;注气后期冲孔钻孔等效直径对增流效果的影响逐渐减小。注气时间小于25d时,等效直径2.4m条件瓦斯抽采纯量明显高于等效直径1.6m 条件。当注气时间大于25d时,两种条件下的瓦斯抽采纯流量逐接近并在后期出现等效直径2.4m条件瓦斯抽采纯流量小于1.6m条件的现象。注气初期注气压力对增流效果影响不大;注气时间逐渐增大时,注气压力对增流效果的影响逐渐减小。钻孔间距对瓦斯增流和消突效果影响并不显著,但钻孔间距较大时可能出现增产滞后现象。因此,虽然较大的冲孔钻孔等效直径与注气压力条件,能有效缩短消突周期,但是注气驱替后期效果并不显著。现场工程试验结果表明,采用低透煤层水力冲孔与注气驱替协同增抽瓦斯技术后,钻孔瓦斯抽采流量最大提高至0.0325m3/min,增流44%~85%。与此同时,钻孔瓦斯抽采浓度最大提高至79.3%,浓度提高了103%~167%。

关键词:

低透煤层 , 水力冲孔 , 注气驱替 , 集中应力 , 多物理场耦合

Abstract:

Abstract: In order to improve the effect of unloading gas extraction by hydraulic punching drilling in low-permeability coal seams and eliminate the negative effect of punching-induced concentrated stress on gas flow, a method of enhanced gas extraction by hydraulic punching and coordinated gas injection and driving is proposed. In order to explore the factors affecting the effect of hydrofluidic punching and synergistic gas injection, a coupled flow-solid model of multi-component gas storage and transportation process was established, and the effects of different punching hole equivalent diameters, gas injection pressures, and drilling spacings on the effect of increasing gas flow and eliminating surges were analysed. The results show that increasing the equivalent diameter of punched holes can significantly increase the pressure unloading range of the coal seam, improve the effect of gas flow enhancement and shorten the period of blasting abatement. Increasing the gas injection pressure can improve the effect of gas flow enhancement, reduce the flow decay per unit time and shorten the period of blasting. Drill hole spacing does not significantly affect the effect of gas flow enhancement and blasting elimination, but the lagging phenomenon of production increase may occur when the drill hole spacing is larger. The equivalent diameter of the punched holes has a significant effect on the gas flow and content at the initial stage of gas injection; the larger the equivalent diameter is, the larger the initial gas flow is and the smaller the initial gas content is. Field engineering test results show that after adopting the synergistic gas extraction technology of hydraulic punching and gas injection in low-permeability coal seams, the maximum gas extraction flow rate of the drilled holes is increased to 0.0325 m3/min, and the flow rate is increased by 44%~85%, which has a good application effect.

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