The Influence of Pipeline Bending Stiffness on 3D Dynamic On-Bottom Stability and Importance for Flexible Flowlines, Cables and Umbilicals

Autor: Matthew Robertson, Graham Viecelli, Aiman Al-Showaiter, Peter Ma, Daniel Carneiro, Stuart Oldfield, Terry Griffiths
Rok vydání: 2015
Předmět:
Zdroj: Volume 5A: Pipeline and Riser Technology.
DOI: 10.1115/omae2015-41646
Popis: In some areas of the world, subsea pipeline hydrodynamic stability is one of the most fundamental aspects of pipeline design. Several design approaches can be used to analyse pipeline stability, ranging from simple force-balance calculations to complex dynamic finite element analysis. Effective and accurate pipeline stability analysis is essential to avoid the potentially high costs associated with complex stabilisation solutions. As it stands the current engineering practices using absolute stability or generalized stability do not explicitly account for pipeline stiffness, hence do not distinguish any difference in response between flexible and rigid pipelines of similar SG and diameter under a given metocean condition. Observations of recent WGK dynamic stability analyses show that pipelines that have identical properties but very different stiffness will exhibit significantly different lateral response under the same metocean conditions. Studies investigating sensitivity of predicted lateral response versus the number of storm random seed realisations have also been observed to show little or no correlation between the peak wave velocity and peak pipeline response. Recognising that in directionally spread wave conditions, peak wave events do not tend to be associated with the widest wave crests in a seastate, this paper will investigate the nature of wave velocity and crest width characteristics leading to pipeline lateral displacement events (width and net movement) within a storm, and how this varies with pipeline stiffness. Further understanding of the mechanisms driving pipeline response are therefore expected, based on the hypothesis that both pipeline stiffness and the crest width of waves capable of causing pipeline displacement are important parameters. It is further anticipated that this will help refine the existing design approaches for flexible pipelines which may not be adequately addressed using existing industry design methods, as well as providing recommendations for the minimum length of 3D dynamic stability models required to be considered in order to accurately capture the longitudinal length scales of importance.
Databáze: OpenAIRE