报告题目： Instabilities in Deep Subsea Pipelines
报告人： 澳大利亚中央昆士兰大学Faris Albermani 教授
Professor Faris Albermani has conducted teaching and research at the University of Queensland (Brisbane, Australia) for 30 years before joining Central Queensland University (Mackay, Australia) in 2017 as a full professor. He has completed research and consultancy projects in various topics such as transmission lines, shell and spatial structures, subsea pipelines, cladding systems, energy dissipation devices in structural engineering. He has 21 PhD candidates successfully completed their research under his supervision and over 90 papers in refereed international journals.
The failure of Deepwater Horizon in the Gulf of Mexico (April 2010) and the resulting oil spill (40,000–60,000 barrels/day) that took months to contain is a reminder of the risk involved in deep sub-sea operations. Other recent incidents are the 1.3 million liters’ oil spill in Guanabara Bay (Brazil, 2000) and the Montara West Atlas rig (Australia, 2009). The environmental and economic impact of these catastrophes is substantial and will take many years to quantify.
Most of the available hydrocarbon reserves are located in remote ultra-deep sub-sea regions (over 1500 m depth) and exploration in such regions poses many engineering challenges. Hence, it is vital to develop engineering solutions that will allow safe and economical realization of these resources. A sub-sea pipeline can experience a number of structural instabilities, such as lateral (snaking) buckling, upheaval buckling, span formation and propagation buckling. Among these, propagation buckling is the most critical one, particularly in deep water, and can quickly damage many kilometres of pipeline. A local buckle, ovalization, dent or corrosion in the pipe wall can quickly transform the pipe cross-section into a dumb-bell (or dog-bone) shape that travels along the pipeline as long as the external pressure is high enough to sustain propagation. The lowest pressure that maintains propagation is the propagation pressure which is only a small fraction of the elastic collapse pressure of the intact pipe. This results in a substantial increase in the material and the installation cost of the pipeline, since design is therefore governed by propagation pressure.
Analytical and experimental results conducted on pipes in a hyperbaric chamber will be presented and discussed and a new pipeline design is proposed that has the potential to increase propagation buckling capacity without increasing the wall thickness of the pipeline. It is expected that this new design will have additional benefits in alleviating other possible instabilities in pipelines.