Jas, E., O’Brien, D., Fricke, R., Gillen, A., Cheng, L., White, D., Palmer, A., (2012) “Pipeline Stability Revisited”, The Journal of Pipeline Engineering

THE STABILITY assessment of the 40-in North Rankin A trunkline, operated by Woodside Energy Ltd, has provided better insight into fluid-soil-pipe interactions during extreme storm events. The resulting conclusion of the work is that the trunkline, a major subsea natural gas artery in Australia’s Northwest Shelf since its installation in 1982, can continue to be operated safely for the next 30 years from a hydrodynamic stability point of view. This conclusion was reached after substantial study and physical model testing was performed considering the tripartite interaction between fluid, seabed, and pipeline. To provide vital information feeding into the stability analysis, a physical model testing programme was developed, and a new world-class hydrodynamic testing facility designed, constructed, and commissioned at the University of Western Australia. This facility allows the replication of near-seabed conditions during tropical cyclones in controlled laboratory conditions, and observation of the interaction between ocean, seabed, and pipeline. Tests were performed using a range of pipeline embedment profiles, storm realizations, and pipe fixity conditions simultaneously to model hydrodynamic loading onto the pipeline and seabed scour. This data were then used in the three-dimensional numerical modelling of pipeline response using finite-element analyses, which included the effects of seabed instability.

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