Abstract
Drill-string vibration excitation longitudinally is a potential drilling method for reducing friction between drill-string and borehole rock. This article assumes that borehole rock surface is composed of elliptical asperities, based on elastic-plastic contact theory, a modified model for friction reduction by vibrating drill-string longitudinally is developed. The results show that the tangential stiffness of borehole rock surface decreased with increasing ovality of asperity. Further, at the same ovality, thin and tall asperity has bigger tangential stiffness than short and fat asperity. Only when the tangential stiffness of borehole rock is greater than a certain threshold, the friction force calculated by proposed model in this paper can appear reverse phenomenon. When the tangential stiffness tends to infinity, the result tends to Coulomb model. The conclusions provide basis for research and application of drill-string vibration longitudinally friction reduction technology.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
