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Our Arctic Neighbors: Pipeline planners deal with ice gouging Industry team to produce recommendations for designing offshore Arctic pipelines to resist massive pressure from ice movement Sarah Hurst For Petroleum News
An international team of 13 industry representatives is trying to solve problems related to offshore pipelines in Arctic regions, Graeme Davis from risk management company Det Norske Veritas said in a presentation at the 4th Norway-Russia Arctic Offshore Workshop in Oslo June 17. The Ice Pipe Joint Industry Project started in June 2008 and a draft report on the team’s findings is due to be released in the first half of 2010.
“During recent years major discoveries of oil and gas reserves have been made in offshore areas of the High North. The oil and gas industry is faced with major challenges in developing and exploiting these resources because of the extreme weather and environmental conditions experienced in these areas. In particular, the Arctic environment introduces challenging new loading conditions to offshore pipelines,” Davis told Petroleum News in an e-mail.
Goal: new recommendations Ice Pipe’s objective is to develop a new recommended practice for Arctic offshore pipelines, Davis said.
“The existing design code structure does not provide implicit or explicit guidance for the design and operation of Arctic pipelines,” he said. “Project-specific design approaches and knowledge retention by key contractors is currently the norm. There is a wide variation in the accepted design principles and probabilistic approaches currently employed to characterize the threats to Arctic pipelines.
“Particular attention is being paid to ice gouging and optimized pipeline burial depth, where assessment methodologies and tools are very much on the cutting edge of technological development. Challenges to the development of safe and sustainable oil and gas activities in the High North are legion; however the list of innovative projects to meet the challenges of the new Arctic frontier is equally as impressive. Joint Industry Projects offer a practical vehicle for optimized development of the tools industry needs to deliver safe and cost-optimized projects in the High North.”
Ice gouges Linear depressions called ice gouges are caused by moving features reaching the seabed such as ice ridges, stamukhi (grounded pressure ridges) and icebergs, Davis said in his presentation. Ice gouges create extremely large forces, with initial studies suggesting theoretical loads in the order of 100 meganewtons. Ice gouges can occur in significant water depths and be several meters deep and wide and several kilometers long. They induce subgouge deformation of the soil.
Some of the ideas being considered in the Ice Pipe project include avoiding the worst-affected areas, burying pipelines to avoid ice-pipe interaction and including explicit consideration of uncertainty in the design of Arctic offshore pipelines. Pipeline designers need to know how to interpret ice gouge measurements, Davis said.
The participants in the Ice Pipe project represent oil and gas majors, contractors, manufacturers and designers: Det Norske Veritas, StatoilHydro, ExxonMobil, ConocoPhillips, Eni Norge, Tenaris, JP Kenny, Technip, Acergy, KBR, Reinertsen, CTC Marine and Canada’s Memorial University.
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