硬地层牙轮钻头破岩特性数值模拟研究

Numerical simulation of rock-breaking characteristics of tri-cone bit in hard formations

摘要:

针对硬地层钻进中牙轮钻头失效频发、寿命短等工程难题，本研究基于现场钻井数据，建立了钻头-岩石非线性接触动力学模型，采用Drucker-Prager准则描述岩石弹塑性行为，通过有限元软件ABAQUS模拟三牙轮钻头在钻压与转速耦合作用下的破岩过程。结果表明：破岩以冲击和剪切为主，其所诱发的拉应力是岩石破坏的主导因素；钻头在破岩过程中存在显著的纵向与扭转振动，其导致的瞬时冲击是加速轮齿磨损和轴承失效的根本原因，该结论与现场失效案例基本一致。研究成果揭示了牙轮钻头在硬地层中的失效机理，并提出优选抗磨损钻头、加装减震器及优化钻进参数等建议，对提升深部硬地层钻进效率与降低工程成本具有重要的理论指导意义和实践应用价值。

Abstract:

To address the engineering challenges of frequent failure and short service life of roller cone bits in hard formation drilling， this study established a nonlinear contact dynamic model between the bit and rock based on field drilling data. The Drucker-Prager criterion was adopted to describe the elastoplastic behavior of the rock. The rock-breaking process of a tri-cone bit under the coupled effects of weight on bit （WOB） and rotary speed was simulated using the finite element software ABAQUS. The results indicate that rock breakage is primarily achieved through impact and shear， with the induced tensile stress being the dominant factor in rock failure. Pronounced longitudinal and torsional vibrations occur during the rock-breaking process， and the resulting transient impacts are the root cause of accelerated tooth wear and bearing failure. This conclusion is consistent with field failure cases. The research reveals the failure mechanism of roller cone bits in hard formations and proposes recommendations such as preferentially selecting wear-resistant bits， installing shock absorbers， and optimizing drilling parameters. These findings provide important theoretical guidance and practical value for enhancing drilling efficiency in deep hard formations and reducing engineering costs.