基于微钻实验台的PDC钻头动载钻进适应性研究

Study on adaptability of PDC bits under dynamic loading based on micro-drilling test rig

摘要:

PDC钻头冲击回转钻进是一种有效提高硬地层机械钻速的方法，但目前PDC钻头冲击回转实验设备大多数不能方便地控制冲击载荷幅值和频率等参数。为了研究未磨损和磨损齿2种PDC钻头在不同的静/动载荷参数下钻速的变化规律，设计制造了不同磨损程度的PDC钻头，并使用改进的伺服给进微钻实验台进行可控动载荷参数的钻进实验，重点分析了静载荷、动载荷方式以及动载荷幅值、占比、频率等参数对钻头钻速的影响规律。结果表明：静载荷钻进时，钻头切削齿的磨损会显著降低钻进效率；动载荷钻进时，完好齿和磨损齿PDC钻头平均钻速分别提高了21.5%和35.2%；动载荷占比和频率对钻速的影响较大，保持轴向最大总载荷不变，随动载荷幅值增加，2种钻头的钻速均呈下降趋势；本实验的参数范围内，2种钻头均在动载荷频率为10 Hz时钻速最优。研究结果揭示了PDC钻头在动载荷下的工作特性，为深井硬地层冲击回转钻进参数优化与钻头选型提供了实验依据。

Abstract:

Rotary-percussive drilling with PDC bits is an effective method for improving the rate of penetration （ROP） in hard formations. However， most existing experimental devices for PDC bit impact rotary drilling lack convenient control over parameters such as impact load amplitude and frequency. To investigate the variation laws of ROP for both unworn and worn PDC bits under different static and dynamic load parameters， PDC bits with varying degrees of wear were designed and manufactured. Drilling experiments with controllable dynamic load parameters were conducted using a modified servo feed micro-drilling test rig， focusing on analyzing the effects of static load， dynamic load mode， as well as dynamic load amplitude， proportion， and frequency on bit ROP. The results indicate that： under static load drilling， the wear of bit cutters significantly reduces drilling efficiency； compared with static load drilling， the average ROP of unworn and worn PDC bits increases by 21.5% and 35.2%， respectively， under dynamic load drilling. The dynamic load proportion and frequency have a significant influence on ROP. With the maximum total axial load kept constant， the ROP of both unworn and worn PDC bits shows a decreasing trend as the dynamic load amplitude increases. Within the experimental parameter range， both types of bits achieved optimal ROP at a dynamic load frequency of 10 Hz. The research results elucidate the operational behavior of PDC bits under dynamic loading conditions， thereby offering an experimental foundation for optimizing drilling parameters and selecting appropriate bits for percussive-rotary drilling in deep hard formations.