煤矿井下卸压钻孔钻杆振荡消除与钻进增效方法研究

Study on drill pipe oscillation elimination and drilling efficiency enhancement of pressure-relief borehole in coal mines

  • 摘要: 卸压钻孔施工是煤矿井下最常见的钻进作业之一,普遍具有直径粗、施工角度多、深度大等特点。由于作业环境条件的限制,诸多卸压钻孔钻进难以直接采用大型钻进设备作业,采用小型钻机配合轻质小直径钻杆完成大直径钻孔钻进是进行此类恶劣环境区域卸压钻孔施工的有效途径,但易出现钻杆剧烈振荡,导致钻进弯曲与效率低下。针对此类问题,提出了一种钻杆振荡消除与钻进增效方法,通过理论分析、数值模拟、实验室试验等综合研究方法,系统分析了小直径钻杆完成大直径钻进工作效率低下、质量不佳的内在原因,以及大直径卸压钻孔钻进的钻杆振动特性与消振机理。结果表明:钻杆剧烈振荡造成的钻孔弯曲、钻机功率额外消耗等因素,是造成钻孔钻进质量不佳与低效的主要原因,钻进深度越大,钻杆振荡越剧烈,钻进效率与质量越低。采用消振装置对钻杆在径向上进行支撑,可消除钻进过程中钻杆振荡,钻进深度越大,消振装置的消振效果愈明显,当钻孔深度为4 m时,钻杆振幅显著减小,最大振幅减小80%。据此,研制了适用于卸压钻孔钻进的静态支撑消振器,它同时具有消振和钻杆连接作用,主要由内嵌式钻杆连接件、轴承结构、锁紧垫片和支撑座组成,钻杆高速旋转作用下其支撑座不随钻杆旋转且支撑于孔壁之上,钻屑可顺利通过导屑通道排出。现场钻进试验结果显示,采用该消振器,当钻进深度为4 m时,钻进时间减少了28%,有效提高了钻进效率与质量。

     

    Abstract: Pressure-relief borehole construction is one of the most common drilling operations in coal mines, which generally has characteristics such as coarse diameter, multiple construction angles, and large depth. However, due to the limitations of the working environment conditions. Many pressure-relief borehole drilling are difficult to directly use large-scale drilling equipment. The use of small drilling rigs combined with lightweight small diameter drill pipes to complete large-diameter drilling is an effective way to carry out pressure-relief borehole construction in such harsh environmental areas. But there will be severe oscillation of the drill pipe, leading to bending and low efficiency in drilling. In response to such issue, a method for eliminating drill pipe oscillation and increasing drilling efficiency has been proposed. Through comprehensive research methods such as theoretical analysis, numerical simulation, and laboratory experiments. The system analyzed the internal reasons for the low efficiency and poor quality of completing large diameter drilling with small diameter drill pipes, as well as the vibration characteristics and oscillation reduction mechanism of drill pipes in large-diameter pressure-relief borehole drilling. The results indicate that the main reasons for the poor quality and low efficiency of drilling are the bending of borehole and the extra power consumption of the drilling rig caused by the severe oscillation of drilling pipe. The larger the drilling depth, the more severe the drill pipe oscillation, and the lower the drilling efficiency and quality. The oscillation damping device is used to support the drill pipe in the radial direction, which can eliminate the drill pipe oscillation during drilling. The greater the drilling depth, the more obvious the oscillation attenuation effect of the oscillation damping device. When the drilling depth reaches 4m, the drill pipe amplitude is significantly reduced, and the maximum amplitude can be reduced by 80%. Based on this, a static support oscillation absorber suitable for pressure-relief borehole drilling is developed, which has both oscillation attenuation and drill pipe connection functions. It is mainly composed of embedded drill pipe connector, bearing structure, locking gasket and support seat. Under the action of high-speed rotation of drill pipe, the support seat not rotate with the drill pipe and is supported on the hole wall, and drilling cuttings can be discharged smoothly through the chip guide channel. The on-site borehole drilling test results show that using this oscillation absorber, when the drilling depth is 4m, the drilling time is reduced by 28%, effectively improving the drilling efficiency and quality.

     

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