Abstract
This paper studies the problems of stick-slip mitigation and speed tuning for a lumped-parameter drill-string system by using a proportional-derivative feedback controller via path-following analysis. In this study, we consider two main control parameters, the weight-on-bit and the desired drill-bit speed. In particular, we determine the combinations of these two parameters for which the proposed control scheme is applicable, which is affected by the non-smooth nature of the system induced by bit-rock interaction. Our analysis using path-following techniques for non-smooth systems reveals the inherent coexistence of stick-slip vibration and constant rotation, and identifies a critical point where the drill-bit speed coincides with the desired angular speed. Furthermore, our analysis proposes a strategy that allows controlling the drill-bit speed to suppress stick-slip, by tuning the controller in a suitable manner.
Highlights
In oil and gas drilling, the drill-string system shown in Fig. 1 includes a rotary table, a series of hollow drill pipes, several relatively thicker drill collars, and a drill-bit
This paper presents a numerical study of stick-slip mitigation and speed tuning for a drill-string system by using a recently developed proportional-derivative (PD) feedback controller
As is well-known, due to the non-smooth nature of the drill-strings induced by bit-rock interaction, the minimum controllable desired rotary speed is, in general, unknown
Summary
In oil and gas drilling, the drill-string system shown in Fig. 1 includes a rotary table, a series of hollow drill pipes, several relatively thicker drill collars, and a drill-bit. We will pay particular attention to these issues and study the proposed controller by considering the desired drill-bit speed and weight-on-bit in terms of the actual angular speeds and stick-slip mitigation. Another goal of the present paper is to study the multistability of the drill-string system under the action of the proposed controller, as well as to investigate the evolution of the resulting coexisting attractors. The main contributions of this work are twofold: first, studying multistability in drill-strings when rotary speed is low, and second, a numerical approach based on path-following techniques that allows controlling rotary speed and stick-slip mitigation by tuning the PD controller in a suitable manner.
Sign-in/Register to view highlights & summary 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.
