Pipelay parametric investigation of pipeline dynamic behaviours for deepwater S-lay operation
Pu Xu, Shunfeng Gong
Abstract
Pipeline installation into deep waters puts higher demands for the laying design. To reveal pipelay parametric effects on the pipeline dynamic behaviours, this study developed a dedicated finite element model (FEM) for deepwater S-lay system in light of OrcaFlex. This FEM sufficiently considered the clashing contacts between the pipeline and stinger rollers as well as pipe-seabed interactions. The effectiveness of the FEM was validated by contrast with the calculated values obtained from an analytical model. A group of real sea state data was collected from a pipeline installation project in the LW3-1 gas field. Extensive numerical analyses of laying pipelines for various pipelay parameters were carried out under the dynamic excitations of surface waves, ocean currents and induced vessel motions. The influences of water depth, effective tension fed from tensioners, stinger length, pipe diameter and submerged self-weight on the pipeline dynamic behaviours were systematically evaluated. A strong relevance between pipelay parameters and pipeline responses was observed, which could provide a practical reference for the deepwater installation design.