Dynamic Model and Quantitative Analysis of Stick-Slip Vibration in Horizontal Well

Baojin Wang,Fushen Ren,Zhongyang Wang

doi:10.1155/2020/8831111

Abstract

Stick-slip is very harmful to the service life of drillstring. The extended Hamilton principle is applied in the paper. Then, finite element method (FEM) is employed to describe the model. The drillstring-borehole impact and friction, fluid-structure interaction, bit-rock interaction, and gravity are considered in this model. The influence of axial and torsional excitation on stick-slip is analyzed. The nonlinear motion predicted by the model is consistent with the observation results in the experiments. The research shows that the fluctuation amplitude of the bit angular velocity also increases along with the increase of driving angular velocity (torsional excitation). However, both the ratio of the maximum angular velocity of the stick-slip vibration and the fluctuation of the angular velocity are continuously reduced. Meanwhile, the strength of the stick-slip vibration has a tendency to slow down. As the axial load (axial excitation) increases, the fluctuation of the maximum angular speed of the stick-slip vibration does not change significantly, but the smaller load causes a smaller stick duration.

Highlights

Rotary drilling system for exploration and development of oil and gas reservoirs in petroleum engineering is widely applied. e drillstring is a series of drilling tools, which may include drill pipes, drill collars, stabilizers, and auxiliary tools. e axial load, torque, bit-rock interaction, slurrydrillstring interaction, and slurry damping have negative effects on the drillstring
Belokobyl’skii and Prokopov research the friction that induces self-excited stick-slip in the early days [9]. ey present a single degree of freedom system with dry friction and think that the nonlinear friction can cause stick-slip
Sarker et al develop a bond graph dynamic model in horizontal well. e friction in this model is divided into two parts, frictions in deflecting section and horizontal section

Summary

Introduction

Rotary drilling system for exploration and development of oil and gas reservoirs in petroleum engineering is widely applied. e drillstring is a series of drilling tools, which may include drill pipes, drill collars, stabilizers, and auxiliary tools. e axial load, torque, bit-rock interaction, slurrydrillstring interaction, and slurry damping have negative effects on the drillstring. A drag-bit model with two degrees of freedom is presented by Zamanian et al in order to study the stick-slip vibration of drillstring.

Results

Conclusion