煤矿井下近水平定向孔无孔底低速磨削悬空侧钻分支技术

Low speed grinding and hang sidetracking branch technology for near horizontal directional hole in coal mine

分支孔是确保定向孔沿目标地层长距离钻进、提高定向钻孔覆盖范围、精准地质异常体探查的关键。分析了煤矿井下主要侧钻分支技术原理与优缺点,以无孔底低速磨削悬空侧钻分支为研究对象,建立了侧钻分支力学模型,给出了分支侧钻侧向力计算公式及影响规律;分析了无孔底低速磨削悬空侧钻分支的动态过程,总结了侧钻初期、中期和末期的钻进要点;建立分支过渡段孔壁稳定性分析数值模型,研究了煤岩体破坏深度对分支过渡段稳定性的影响,给出了分支过渡段安全钻进建议。在成庄矿和祁东矿进行了枝状煤层定向孔、底板梳状定向孔钻进应用,单孔最大分支数量达到77个,侧钻成功率100%,安全性100%,为煤矿井下近水平定向孔作用的发挥提供了技术保障。

The branch hole is the key to ensure the long-distance drilling of directional hole along the target stratum, improve the coverage of directional drilling and accurately explore geological abnormal bodies. The principle, advantages and disadvantages of the main sidetracking branch technology in coal mine were analyzed. Taking the low speed grinding and hang sidetracking branch without hole bottom as the research object, the sidetracking branch mechanical model was established, and the calculation formula and influence law of the lateral force of the branch sidetracking was given;the dynamic process of hang sidetracking was analyzed,and the drilling points in the initial, middle and final stages of sidetracking were summarized;the numerical model of branch transition section stability analysis was established, the influence of coal and rock mass failure depth on the stability of branch transition section was studied, and the suggestions for safe drilling in branch transition section were given. The field application were carried out in Chengzhuang Mine with branch coal seam directional hole and Qidong Mine with comb floor directional hole,the maximum number of branches in a single hole is 77, the sidetracking success rate is 100% with the safety is 100%, which will provides a technical guarantee for the role of near horizontal directional hole in coal mine.