ADVANCES IN DESIGN AND INSTALLATION ANALYSIS OF PIPELINES IN CONGESTED AREAS WITH ROUGH SEABED TOPOGRAPHY

摘要

The present paper addresses a method for simulation of deepwater pipeline installation in offshore fields with rough seabed topography focusing on verification of installation feasibility. The method enables 3D pipe lay analysis to be carried out as a set of subsequent static analyses where the vessel is moved forward automatically considering the restraints from lay vessel departure angle and arbitrarily curved pipe routing. The analysis includes the effect of seabed topography from survey data and variable seabed conditions. The numerical algorithm is seamlessly integrated with 3D graphics for visualization of both the seabed terrain and the structural response of the pipe as the vessel is moving forward. The numerical method is based on finite elements that are formulated by applying the Principle of Virtual Displacements. Large deformations, non-linear geometry and contact effects are taken into account. In addition, elastic and elastic-plastic material models are allowed for, both for the pipe and the seabed contact elements. The paper focuses on the procedure including a brief theory description addressing the specialities needed in this case with respect to kinematics, material models and finite element formulation. The developed procedure is then demonstrated both by analytical and real pipeline installation test examples.