Dynamic Analysis of Percussion Drilling System under Harmonic Impact

Yijin Zeng,Jinchao Xu,Qunai Hu,Shidong Ding,Xiaojie Cui,Wenjun Huang

doi:10.1155/2021/8892144

Abstract

As a new efficient rock-breaking technology, harmonic impact drilling technology has received great attention, but the research on its rock-breaking mechanism is insufficient, which limits its development. Based on the theory of vibration, a simplified model of high-frequency harmonic vibration impact system is established in this paper. The numerical model was solved by Matlab and the motion equations of drill bit and rock at different stages of motion are obtained, respectively. Based on the factor analysis of the mathematical model, the dynamic characteristics of the impact system under harmonic excitation are studied. Finally, numerical simulations are carried out to further analyze the drilling effect of harmonic impact drilling and verify the correctness of the simplified model. The results show that when the excitation frequency equals the resonance frequency of rock, the vibration displacement of rock reaches the peak value. The drilling speed is greatly increased by harmonic impact drilling compared with conventional drilling.

Highlights

Harmonic impact drilling technology is an emerging efficient rock-breaking method that is developed by the Centre for Applied Dynamics Research (CADR) at the University of Aberdeen to improve the rate of penetration in hard formation [1, 2]. e technology is realized by applying harmonic impact to the rock combining the appropriate drilling pressure and rotational speed
No impact force is exerted in conventional drilling compared with harmonic impact drilling. e following discussion on the simulation results will be carried out from the perspective of axial motion and torsional motion of the drill bit
And 10, the axial drilling characteristics of conventional drilling and harmonic impact drilling are presented. In both drilling methods, the progression of the drill bit increases in a stepwise form with the increase of time due to the stick-slip effect. It can be obtained from the simulation results that, under the same drilling conditions, the maximum rate of penetration (ROP) is 39.59 mm/s and the average ROP is

Summary

Introduction

Harmonic impact drilling technology is an emerging efficient rock-breaking method that is developed by the Centre for Applied Dynamics Research (CADR) at the University of Aberdeen to improve the rate of penetration in hard formation [1, 2]. e technology is realized by applying harmonic impact to the rock combining the appropriate drilling pressure and rotational speed. Harmonic impact drilling technology is an emerging efficient rock-breaking method that is developed by the Centre for Applied Dynamics Research (CADR) at the University of Aberdeen to improve the rate of penetration in hard formation [1, 2]. By comparison with the rock-breaking effect of conventional drilling, the advantages of harmonic impact drilling technology were verified. There were a few researches on the fundamental rock-breaking mechanism of the technology. Li et al [15, 16] analyzed the rock-breaking mechanism of drill tool under harmonic vibroimpacting both theoretically and experimentally. E innovation of the paper is the dynamic analysis of percussion drilling system under the harmonic impact which is conducted from both percussion drilling model and numerical simulations, and the drilling effect of the harmonic impact technology is proved

Simplified Model

Numerical Simulation of Harmonic Impact Drilling

Conclusion