煤矿井下小直径定向钻进轨迹控制技术研究进展与展望

Research advances and prospects in trajectory control technologies for small-diameter directional drilling in underground coal mines

摘要:

为明确煤矿井下小直径定向钻进轨迹控制的关键问题与发展方向，面向长距离近水平钻孔对轨迹精度、成孔稳定性和施工效率的需求，系统梳理了轨迹偏斜机理、轨迹控制工具、随钻测量与近钻头感知、轨迹预测及智能控制等方面的研究进展。分析表明：煤层、夹矸、碎软煤体、硬质顶底板及构造破碎带等复杂地质条件交替分布，导致钻头受力、孔壁稳定性、钻压传递和岩屑返排状态不断变化，易引起顺层偏离、软硬界面穿层偏斜、硬岩段纠斜效率降低及长距离轨迹偏差累积；小直径条件进一步限制螺杆马达、稳定器、测量短节、供电通信模块和排渣通道的协同集成。现阶段，单弯螺杆钻具仍是主动造斜与纠斜的基础工具，复合定向、旋转导向、PDC钻头、多动力组合钻具和多参数随钻测量可在稳斜、破岩、清孔和反馈方面提供补充，但其小直径适配能力、复杂煤系地层中的运行可靠性及现场闭环验证仍显不足。未来应强化偏斜机理与工程数据耦合，发展小型化近钻头感知和稳定传输技术，推动机理模型与数据驱动模型融合，并将预测结果转化为工具面角、钻压、转速及滑动/回转切换等可执行参数，形成“感知、预测、决策、执行、校验”闭环控制体系。

Abstract:

To clarify the key issues and development directions of borehole trajectory control for small-diameter directional drilling in underground coal mines， this paper systematically reviews research progress in borehole deviation mechanisms， trajectory-control tools， measurement while drilling， near-bit sensing， trajectory prediction， and intelligent control， with emphasis on the requirements of long-distance near-horizontal boreholes for trajectory accuracy， borehole stability， and drilling efficiency. The analysis shows that the alternating distribution of coal seams， partings， broken soft coal， hard roof and floor rocks， and structural fracture zones causes continuous variations in bit loading， borehole stability， weight-on-bit transfer， and cuttings transport conditions. These variations may result in deviation along bedding planes， cross-layer deviation at soft-hard interfaces， reduced efficiency of borehole deviation correction in hard-rock intervals， and cumulative borehole-trajectory errors in long-distance drilling. Small-diameter conditions further constrain the coordinated integration of positive displacement motors， stabilizers， measurement subs， power-supply and communication modules， and cuttings-removal passages. At present， single-bend positive displacement motors remain the basic tools for deflecting and borehole deviation correction. Compound directional drilling， rotary steerable drilling， PDC bits， multi-power drilling assemblies， and multi-parameter measurement-while-drilling systems provide complementary functions in angle holding， rock breaking， flushing and cuttings removal， and information feedback. However， their adaptability to small-diameter boreholes， operational reliability in complex coal-measure strata， and field validation of closed-loop control remain insufficient. Future research should strengthen the coupling between borehole deviation mechanisms and engineering data， develop miniaturized near-bit sensing and reliable data-transmission technologies， promote the integration of mechanism-based and data-driven models， and convert prediction results into executable parameters， including tool face angle， weight on bit， rotary speed， pump discharge， and switching between sliding drilling and rotary drilling， thereby establishing a closed-loop control system integrating sensing， prediction， decision-making， execution， and verification.