冲击地压矿井内排式钻屑法钻屑运移规律研究及应用

Transportation patterns of drilling cuttings and application using the internal row drilling cuttings method in rockburst mines

  • 摘要: 为了解决钻屑法作业过程中钻屑量采集不准确的问题,发明内排式钻屑法以及相应的钻具,其原理是通过负压将钻屑从钻具的内部通道运移至孔外,并对钻屑进行采集与称重。对负压条件下钻屑的运移规律进行理论分析,并采用CFD-DEM耦合数值模拟方法,研究钻屑运移通道的不同结构形式对钻屑-气体流动特征的影响规律,结合数值模拟结果对内排式钻屑法的钻杆进行加工,并通过室内试验验证内排式钻屑法收集钻屑的可行性。结果表明,压强差越大,钻屑运移越快;在同一负压和钻速条件下,钻具端头的流体孔截面大小与负压运输钻屑的效率呈正比;增加流体孔的个数,有利于提升负压运输钻屑的效率;当流体孔向钻头方向倾斜30°时,其负压运输钻屑的效果更好。

     

    Abstract: This study proposes an internal discharge drilling cuttings method and corresponding drilling tools as a solution to inaccurate collection of drilling cuttings in existing drilling cuttings methods. Its mechanism is to transport drilling cuttings out of the hole tiorough the internal channel of the drilling tool by negative pressure. The drilling cuttings were collected and weighed. Their transportation patterns under negative pressure were analyzed via theoretical analysis.The CFD-DEM coupled numerical simulation was conducted to study how different structures of transportation channels influence the drilling cutting-gas flow. The drilling rod was processed based on the numerical simulation results. Laboratory experiments were conducted to verify the feasibility of drilling cuttings collection by the internal discharge drilling cuttings method. Results indicate that 1) Higher pressure differences lead to faster transportation of drilling cuttings; 2) Under the same negative pressure and drilling speed, the cross-sectional size of the fluid hole at the end of the drilling tool is directly proportional to the efficiency of drilling cuttings transportation under negative pressure; 3) Increasing the number of fluid holes could promote the efficiency of drilling cuttings transportation under negative pressure; 4) When the fluid hole is tilted 30 degrees towards the drill bit, it exhibits the optimal transportation performance of drill cuttings under negative pressure.

     

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