Non-Linear Dynamic Analysis of Drill String System with Fluid-Structure Interaction

Abstract

In this research, the non-linear dynamics of the drill string system model, considering the influence of fluid—structure coupling and the effect of support stiffness, are investigated. Using Galerkin’s method, the equation of motion is discretized into a second-order differential equation. On the basis of an improved mathematical model, numerical simulation is carried out using the Runge—Kutta integration method. The effects of parameters, such as forcing frequency, perturbation amplitude, mass ratio and flow velocity, on the dynamic characteristics of the drill string system are studied under different support stiffness coefficients, in which bifurcation diagrams, waveforms, phase diagrams and Poincaré maps of the system are provided. The results indicate that there are various dynamic model behaviors for different parameter excitations, such as periodic, quasi-periodic, chaotic motion and jump discontinuity. The system changes from chaotic motion to periodic motion through inverse period-doubling bifurcation, and the support stiffness has a significant influence on the dynamic response of the drill string system. Through in-depth study of this problem, the dynamic characteristics of the drill string can be better understood theoretically, so as to provide a necessary theoretical reference for prevention measures and a reduction in the number of drilling accidents, while facilitating the optimization of the drilling process, and provide basis for understanding the rich and complex nonlinear dynamic characteristics of the deep-hole drill string system. The study can provide further understanding of the vibration characteristics of the drill string system.

Experimental Study on Vibration of a Rotating Pipe in Still Water and in Flow

“…Riserless drilling is significant for ocean exploration [1][2][3]. As the core component of riserless drilling, under flow and rotation, flow-induced vibration seems to increase the damage to the drilling pipe, and the phenomenon of flow-induced vibration of the drilling pipe has attracted extensive attention from scholars [4][5][6][7].…”

Development of a software module for modeling drill string displacements

“…Ytrehus J. et al [2] experimentally studied the impact of different drilling fluids on mechanical friction. In the work [3], a nonlinear dynamic model of the drill string system taking into account the influence of fluid-structure interaction and the effect of support stiffness was developed. The authors in [4] considered the dynamics of a drill string in a deviated well, described by a nonlinear dynamic model with four degrees of freedom, taking into account the lateral and torsional deformation of the drill string, fluid damping effects, and the stick-slip phenomenon.…”