机械科学与技术2017，Vol.36Issue(3)：347-353,7.DOI:10.13433/j.cnki.1003-8728.2017.0304
硬地层复合钻头破岩特性与提速机理研究
Studying Rock Breaking Properties and Penetration Rate Improving Mechanisms for Hybrid Drill Bit in Hard Formation
摘要
Abstract
A hybrid drill bit combines the structural features and working principles of PDC drill bit and cone drill bit,being able to drill hard formation more efficiently.But its research and development is blind and its promotion is limited due to lack of knowledge about its rock breaking mechanisms.Based on elastoplastic mechanics and rock breaking theory,3D non-linear dynamic simulation models of dynamic rock breaking with full-gauge hybrid drill bit and PDC bit are established with the finite element method.The constitutive relation of rock is described by Drucker-Prager criteria and the plastic strain is used as the criterion for describing the rock breaking.The failure mechanisms for rock breaking in hard formation with the hybrid drill bit are studied.The dynamic rock breaking with hybrid drill bit in hard formation are compared with that of PDC drill bit.The comparison results show that the well drilled by hybrid drill bit can satisfy the borehole wall stability requirements but that the sidewall rock may fall off.This partly explains the reasons why the use of hybrid drill bit significantly enhances the penetration rate in hard formation and why the rock is broken mainly by tensile stress.The torsional vibration of hybrid drill bit is lower than that of PDC drill bit and the rock breaking efficiency is higher in hard formation.The impact of hybrid drill bit on rock is greater than that of PDC drill bit due to the polygon effect of cone drill bit during scrolling;therefore the hybrid drill bit can drill rock faster than PDC drill bit in hard formation.关键词
硬地层/复合钻头/破岩过程/破岩特性/提速机理Key words
hard formation/hybrid drill bit/rock-breaking properties/penetration rate improving mechanism分类
能源科技引用本文复制引用
李琴,谢豆,黄志强,邓嵘,于德良,袁媛..硬地层复合钻头破岩特性与提速机理研究[J].机械科学与技术,2017,36(3):347-353,7.基金项目
国家科技重大专项课题项目(2008ZX05022-006)资助 （2008ZX05022-006）
