J P Kenny, part of international energy services company John Wood Group PLC ("Wood Group"), has developed a three-dimensional (3D) finite element model for investigating the effects of permafrost, permanently frozen soil, on arctic pipelines. The evaluation aids the selection of proper construction and implementation methods used to minimize the impact to the permafrost and the surrounding environment.
Permafrost covers approximately 20 percent of the world's landmass, including half of Canada and Russia, much of northern China and 85 percent of Alaska. Permafrost, which is rich in organic carbon, varies in depth, continuity and ice content. While seasonal thawing of permafrost supports marsh and tundra ecosystems, ground thawing also releases methane and carbon dioxide into the atmosphere and jeopardizes the stable base of constructed facilities such as pipelines.
J P Kenny's 3D model allows the study of the interaction between buried pipelines transporting warm hydrocarbons and the surrounding permafrost. If heat is lost from a pipeline, the heat is transferred to the permafrost, causing it to melt. As a result, the soft, thawed ground around the pipeline looses support and settles, causing strains on the pipeline. J P Kenny's new model gives a more accurate prediction of the amount of thawed ground around the pipe and corresponding strains on the pipeline. Results of the analyses can be used during the initial pipeline design phase to improve safety and cost effectiveness, and to assess existing pipelines embedded in permafrost soils.
"The increasing demand to explore and develop fields in arctic regions makes this model a valuable addition to our arctic tools and allows a greater understanding for assessing pipelines in permafrost conditions," said Alan Brackenridge, president of J P Kenny in Houston.
J P Kenny has extensive arctic experience and has provided its expertise to a number of projects including a consortium, comprising Gazprom, Total and StatoilHydro, for a trunkline project that will bring gas from the Shtokman field in the Barents Sea to Northern Russia. In 2008, it developed a new module that replicates the response of buried pipeline under ice-gouging conditions. J P Kenny collaborates with Wood Group sister company IMV Projects and with the Memorial University of Newfoundland (MUN) in St John's, Canada to develop leading-edge solutions for engineering in arctic regions. Wood Group formed a partnership with MUN in January and is donating C$500,000 for the sponsorship of the Wood Group Chair in Offshore Engineering for Arctic and Harsh Environments, focused on oil & gas engineering in cold regions.