Arctic pipeline simulator models ice-gouging

JP Kenny is using new multi-physics simulation technology to ensure that arctic oil pipelines can withstand gouging from ice formations.

Offshore staff

Houston -- JP Kenny is using new multi-physics simulation technology to ensure that arctic oil pipelines can withstand gouging from ice formations.

The technology from SIMULIA, the Dassault Systèmes brand for realistic simulation software, helps overcome some of the obstacles of other numerical methods used by pipeline engineers.

"Burying pipelines is very expensive. With this technology, you don't have to bury it too deeply," says Paul Jukes, advanced engineering group and pipeline manager for JP Kenny.

Ice gouging is one of the major obstacles for pipeline engineering in the arctic. This is especially relevant given environmental worries as technologies emerge to contend with arctic exploration and production challenges.

The arctic region, mostly offshore, holds as much as 25% of the world's untapped reserve of hydrocarbons according to the US Geological Survey.

However, much of the reserve is located under seasonal or year-round sea ice. This means additional challenges for the design, construction and operation of offshore installations, tending to make such operations expensive.

The presence of fisheries, rare species, and the slow recovery from spills, not to mention the sheer volumes of oil and gas in the arctic, means that pipeline design parameters will have to take into consideration the numerically complex behavior of ice over deformities on the seafloor.

Using simulation results, calculated on a desktop computer, can help engineers determine how deep to bury arctic pipelines, providing significant reductions in installation costs and helping to ensure that sensitive ecosystems are protected.

The engineering firm's Advanced Engineering Group has recently implemented a new module based on SIMULIA's Abaqus Coupled-Eulerian Lagrangian (CEL) technology that will form part of JP Kenny's SIMULATOR set of tools.

The technology uses a 3-D finite element model of pipeline, seabed soil and iceberg. The module uses Abaqus CEL technology to analyze extreme deformations of the seabed undergoing ice gouging.

The CEL technology is distinct from modeling technologies that use Arbitrary Lagrangian Aulerian (ALE) analysis.

"The importance of this numerical method [CEL], besides being reliable and accurate, is that it overcomes the major short comings of other numerical methods such mesh distortion and convergence problems," Jukes says.

This is particularly important, he says, since "most of the up to date studies of the ice gouging have been conducted experimentally, and yielded inconsistent results."

Pipeline design must include parameters such as ice impact, gouging by icebergs or ice keels, assessment of uncertainty related to ice scour events, and ice-soil-pipe interaction.

Using this tool can help attain significant savings by realistically modeling sub-gouge soil deformation with no unnecessary conservatism, Jukes says.

Pinpointing these parameters could significantly reduce calculated required pipeline burial depth ensuring protection for the arctic ecosystem.

In the future, the technology could also be adapted for other subsea applications where extensive modeling is required, Jukes says.

11/13/2008

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