井眼形成是通过钻头牙齿破碎岩石形成岩屑来实现的,对钻头牙齿侵入破岩机理的认识有助于优化钻头结构,提高工具破岩效率。阐述了钻头牙齿与岩石相互作用机理的复杂性,分别从弹性力学、裂纹扩展、数值模拟等几个方面,综述了钻头牙齿与岩石相互作用机理的研究进展,指出了今后的研究重点。虽然前人开展了众多的物理实验与数值模拟研究,但是由于钻头牙齿破岩过程及井底环境的复杂性,目前为止其机理并没有被完全认识清楚。理论与实验研究证明,井底压力是影响机械钻速的重要因素之一,针对钻头牙齿与岩石相互作用机理的复杂性,建议采用先进实验和数值模拟技术,将物理实验和数值模拟结合开展研究,揭示井底复杂应力环境下钻头牙齿的破岩机理将成为未来的研究重点。
The wellbore is achieved by breaking the rock with bit-tooth.A well understanding of rock breakage mechanisms is helpful to optimize the structure of cone bit which can improve the efficiency of drilling tool.The complexity of interaction mechanisms between rock and bit-tooth is elaborated.Advances in the interaction mechanisms between rock and bit-tooth are summarized from the elastic mechanics,crack extension,numerical simulation,and so on,and some advices for the future research are proposed.Although many physical experiments and numerical simulations have been conducted by predecessors,the mechanism has not been fully understood due to the complexity of rock breaking process.Bottom hole pressure is one of the most important factors influencing drilling efficiency which has been proved by theoretical and experimental studies.For the complexity of interaction mechanisms between rock and bittooth,we introduce new theory,adopt advanced experimental technology,and combine the physical experiment with the numerical simulation to carry out theoretical research and reveal the breakage mechanisms between rock and bit-tooth under the complex downhole stress environment.