Simulation of drill-string systems with fluid-structure and contact interactions in realistic geometries

We propose a method for the simulation of the nonlinear dynamics of drill-string systems and the assessment of the stresses to which the pipe is subject under realistic conditions in drilling operations. The formulation of the evolution equations of the drill-string is based on the special Euclidean strand equations for the stresses and momenta of geometrically exact viscoelastic rods. For the spatial discretisation, we employ a finite-difference method on a staggered grid and the time integration is based on an adaptive Runge-Kutta method. The model allows to simulate the nonlinear dissipative dynamics of rods, with realistic material parameters, confined inside tubular wells of arbitrary shape, accounting for fluid-structure and contact interactions. The comparison of the numerical results with field data collected in drilling operations shows the effectiveness of our method in reproducing the mechanical response of real drill-string systems and the robustness in providing accurate predictions when tested in computationally-challenging settings.