摘要
高频扭转冲击钻井作为一种新兴钻井技术,由于其在硬地层钻进中具有显著的提速效果以及能够较好抑制黏滑振动的发生而得到极大关注。但由于对其破岩机理以及提速机理认识不够清楚,使得高频扭转冲击钻井技术在推广应用时尚未发挥其最佳性能。基于有限元法建立了单齿扭转冲击切削岩石的拟三维数值仿真模型,研究了扭转冲击作用下钻齿切削岩石过程中的裂纹扩展、岩屑形成、损伤演化以及破岩比功等问题。研究结果表明:扭转冲击切削作用下岩石相比常规切削更易发生脆性破碎(体积破碎)形成大块岩屑;扭转冲击切削作用下的破岩比功要明显小于常规切削,且岩石单元从损伤萌生到刚度完全退化的时间同样要小于常规切削作用;在软地层中扭转冲击切削几乎没有提速效果。研究结果可为扭转冲击器及钻头设计、钻井参数优选提供依据。
The high-frequency torsional impact drilling is a new emerging drilling technology,which has attracted great attention because of the significantly rising rate of penetration(ROP)and the ability of better restraining the stick-slip vibration in drilling hard formations.However,due to unclear understanding of the rock breaking and ROP rising mechanism,the best performance of highfrequency torsional impact drilling technology has not been executed in promotion and application.Based on the finite element method,the quasi-3D numerical simulation model for single-tooth high-frequency torsional impact is established to study the crack propagation,debris formation,failure evolution,rock-breaking specific work and other problems of drilling-tooth rock cutting under torsional impact.The results show that the brittle failure(volume breaking)is more prone to happen in rocks under torsional impact cutting rather than conventional cutting,thus forming massive debris;the rock-breaking specific work is significantly less and the time of rock unit from failure occurrence to total stiffness degradation is also less under torsional impact cutting than under conventional cutting;the torsional impact cutting nearly has no ROP rising effect in soft formations.The research results can provide an important basis for the torsional impact tool and drilling bit design as well as drilling parameter optimization.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2017年第5期578-586,共9页
Acta Petrolei Sinica
基金
国家自然科学基金项目(No.51674214)
四川省科技计划国际合作计划项目(2016HH0008)
四川省青年科技创新研究团队项目(2017TD0014)资助
关键词
扭转冲击
切削破岩
提速机理
破岩比功
有限元法
torsional impact
rock cutting
ROP raising mechanism
rock-breaking specific work
finite element method
