Numerical and experimental studies of stick-slip oscillations in drill-strings.

Abstract

The cyclic nature of the stick-slip phenomenon may cause catastrophic failures in drill-strings or at the very least could lead to the wear of expensive equipment. Therefore, it is important to study the drilling parameters which can lead to stick-slip, in order to develop appropriate control methods for suppression. This paper studies the stick-slip oscillations encountered in drill-strings from both numerical and experimental points of view. The numerical part is carried out based on path-following methods for non-smooth dynamical systems, with a special focus on the multistability in drill-strings. Our analysis shows that, under a certain parameter window, the multistability can be used to steer the response of the drill-strings from a sticking equilibrium or stick-slip oscillation to an equilibrium with constant drill-bit rotation. In addition, a small-scale downhole drilling rig was implemented to conduct a parametric study of the stick-slip phenomenon. The parametric study involves the use of two flexible shafts with varying mechanical properties to observe the effects that would have on stick-slip during operation. Our experimental results demonstrate that varying some of the mechanical properties of the drill-string could in fact control the nature of stick-slip oscillations.

Citation

LIU, Y., PÁEZ CHÁVEZ, J., DE SA, R. and WALKER, S. 2017. Numerical and experimental studies of stick-slip oscillations in drill-strings. Nonlinear dynamics [online], 90(4), pages 2959-2978. Available from: https://doi.org/10.1007/s11071-017-3855-9

• Journal Article Type: Article
• Acceptance Date: Oct 7, 2017
• Online Publication Date: Oct 31, 2017
• Publication Date: Dec 31, 2017
• Deposit Date: Dec 1, 2017
• Publicly Available Date: Dec 1, 2017
• Journal: Nonlinear Dynamics
• Print ISSN: 0924-090X
• Electronic ISSN: 1573-269X
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• Volume: 90
• Issue: 4
• Pages: 2959-2978
• DOI: https://doi.org/10.1007/s11071-017-3855-9
• Keywords: Drill string; Stickslip; Multistability; Dynamical system; Numerical continuation
• Public URL: http://hdl.handle.net/10059/2612