A multibody dynamic model of the drilling system with drilling fluid

Abstract

This article is intended to present a multibody dynamic model of the drilling system, consisting of drillstring and drilling fluid. The drillstring is a complex rigid-flexible coupling system, including rigid bodies, Euler-Bernoulli beam elements, constraints and dynamic loads, and its dynamic model is established using the absolute nodal coordinate formulation. The drilling fluid, composed of internal, annulus, and under-bit fluids, is modeled as one-dimensional compressible fluid; the relative flow of the drilling fluid is modeled using the Arbitrary Lagrangian-Eulerian description; the force of the drillstring acting on the drilling fluid is introduced through the drilling fluid transport motion; meanwhile, the reaction force acting on the drillstring is taken as an external load. The contact between the drillstring and drilling fluid is simulated based on Hertz contact theory, and the rock penetration model is built based on the rock-breaking velocity equation. Based on this model, the coupled vibration of the drillstring and the effects of the drilling fluid flow rate and density on the drilling process are investigated through several examples.

Development of a software module for modeling drill string displacements

“…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. Ma Y. et al [5] created a fluid-solid coupling model of the drilling system, simulating the dynamics of the drilling system with underlining the effects of a drilling fluid. In [6], the authors established an experimental setup and investigated the mass effect of the internal and external drilling fluids through the batch of experimental and numerical studies.…”

Effect of Annular Gas‐Liquid Two‐Phase Flow on Dynamic Characteristics of Drill String

“…Chang et al [3] and David Ytrehus et al [4]investigated the effect of different types of drilling fluids on the vibration characteristics of the drill string. Salehi and Moradi [5], Tran et al [6], Ma et al [7], and Chen et al [8] studied the effects of density, flow rate, frequency, and other parameters of drilling fluid on the drill string vibration characteristics. Cao et al [9] studied the interaction between the internal fluid and the string of oil and gas wells.…”