The cost-effectiveness of transporting gas depends on the size and length of the pipeline, and at such depths, this poses a challenge that calls for innovative thinking. Statoil ASA, the owner of the Polarled project, has engaged Ramboll’s specialists to design the pipeline.
“If we want to make transporting gas cost-effective, we need to have as much gas running through the pipelines as possible. In deep water, the extreme external pressure makes the largest pipelines difficult to use,” says Per Jørgensen, Senior Director at Ramboll Oil & Gas.
Technology as inaccessible as the gas
So how do you build a large and cost-effective pipeline at such extreme water depths?
It takes highly demanding technical optimisation and advanced technology to reach the hard-to-access gas resources. But only a few engineers possess the knowhow needed to design a subsea project of this scale and complexity. To meet the challenge, specialists have developed new models for assessing complicated 3D design.
Ramboll Project Manager Lars Eriksen explains:
“The project size offers huge possibilities for optimizing the various technical solutions. In particular, we have developed finite element models for assessing very complicated 3D designs. The models give us an exceptional understanding of the true physical behaviour of the pipeline, thus enabling us to optimise its design.”
Ongoing innovation of software solutions
Ramboll is constantly developing new software tools to model the complexities of the Polarled pipeline and streamline its design. One such tool under development will determine the fatigue life of the free-spanning pipeline, as the pipeline has to run through rough, uneven seabed terrain. The tool will use ANSYS to analyse Eigen frequency and Mathlab to classify Eigen frequency and calculate hydrodynamic loading and fatigue.
“The investment made in developing these tools in-house will become extremely valuable in future projects, as we can activate them on new projects, too. You simply cannot buy these tools on the market. They will enable the fast execution of projects in a wide array of design disciplines,” says Kristoffer Bergholt, Project Engineering Manager and Team Leader in the Pipelines & Subsea.
The software tools enabled the team to deliver a comprehensive Front-End Engineering Design (FEED) to Statoil, who will use it as an example for future projects to follow.
About the Polarled pipeline project
- The Polarled Pipeline Project comprises a 36", 481 km gas transmission pipeline from the Aasta Hansteen field, located in the Norwegian Sea, to the Nyhamna gas facility in western Norway• A pipeline to the Barents Sea is expected to be a natural expansion of the Polarled pipeline, potentially adding another 1,000 km
- Ramboll’s work encompasses FEED, detailed design, route optimisation, pipeline tie-in, geotechnical foundation design, risk and safety, environmental impact assessment (EIA) and interface coordination
- Project period: 2013–2016
- Budget: NOK 25 billion