A STATIC DRILLING RISER MODEL USING FREE-BOUNDARY CONDITIONS

A static three-dimensional analytical method for drilling risers exper iencing large displacements and slip at the top joint is presented. Th e riser is described in cylindrical coordinates as a three-dimensional tensioned string, without bending or torsional stiffness. The vertica l vessel displacement is not taken into account. The equilibrium confi guration is obtained from the stationary condition of the total potent ial energy functional. Kinematic boundary conditions are introduced fo r the radial displacement only. The riser orientation at the top direc tly follows from the natural boundary conditions based on the variatio nal treatment of the energy functional. Copyright (C) 1997 Elsevier Sc ience Ltd.