Optimization of Rotary Axial Percussion Drilling

Abstract

Abstract. Rotary axial percussion drilling is a high-speed drilling technology that has been widely applied. However, the traditional single-impactor arrangement has low drilling efficiency, is prone to intensify drillstring vibration, and increases the risk of drillstring failure. To address these problems, this study proposes a rotary axial percussion drilling scheme with multiple impactors. A combination of physical experiments and numerical simulations is used to analyze the sensitivity of drilling performance to different drillstring configurations, impact load levels, and load distribution methods. Results show that (1) the multi-impactor scheme improves the stress condition of the drillstring and helps reduce the risk of failure; (2) it significantly increases the rate of penetration and reduces torsional and axial vibrations. Adjusting the impact amplitude improves drilling efficiency, while changing the impact frequency helps reduce axial vibration; (3) stress waves naturally change during transmission, which allows the impactors to operate at the same frequency but different phases. This phase difference reduces resonance risk at a lower cost and improves drilling performance.