Polarled gas pipeline is a 480km long pipeline planned to be laid between the Aasta Hansteen field in the Norwegian Sea and the Nyhamna gas processing facility in western Norway. The pipeline will have a diameter 36in and capacity of 70 million cubic metres per day.
The project, which was earlier known as the Norwegian Sea Gas Infrastructure (NSGI) scheme, will require an estimated investment of Nrk25bn ($4.3bn). It is expected to set a world record in deep water installation of a pipeline. The pipeline is expected to become operational in late 2016.
The project is being undertaken by a joint venture of Statoil (50.331%), Petoro (11.946%), OMV (9.073%), Shell (9.019%), Total (5.110%), RWE Dea (4.791%), ConocoPhillips (4.452%), Edison (2.396%), Maersk Oil (2.396%), and GDF Suez (0.486%). Gassco will be the operator of the pipeline.
Statoil submitted the plan for installation and operation of the natural gas pipeline on behalf of the partners to the Ministry of Petroleum and Energy, in January 2013. The company also presented the plan for development of the Aasta Hansteen field at the same time.
The aim of the Polarled pipeline project is to create gas transport infrastructure for discoveries already made in the Norwegian Sea and future discoveries. This will help in maintaining the Norwegian Continental Shelf’s role as a reliable gas supply source in the future.
Aasta Hansteen field and Polarled pipeline development project
Aasta Hansteen field is located in the Norwegian North Sea. The field development includes the installation of a SPAR platform which will be tied-in with the Polarled gas pipeline. The field is estimated to contain 47 billion cubic metres of gas. It is expected to start production in the third quarter of 2017 at the rate of 130,000 barrels of oil equivalent per day.
The project also includes the expansion and upgrade of the Nyhamna processing plant.
Design of the Polarled natural gas pipeline
The Polarled pipeline will start from the Aasta Hansteen field. The pipeline will be installed in water depths of 1,300m, about 300km west of Bodø. Construction of the pipeline is expected to require 325,000t of steel pipes worth Nrk 2bn ($347m) and will include pipes, bends and buckle arrestors.
The project is also planned to include a 30km long, 18in diameter spur to the Kristin platform which will connect the pipeline to the Åsgard Transport system. Tie-ins to the Linnorm discovery through Draugen field and to the Zidane field through Heidrun discovery, and 60km and 173km spurs are also being planned.
Polarled gas pipeline route and construction
The route of the pipeline falls in the strait of Bjørnsundet and along existing subsea pipelines. Selection of the route, therefore, required specialised design. The route follows the contours of the strait and will cross the Polar circle. The route selection also required optimisation of pipeline wall thickness and design of the buckle arrestor.
The pipeline will pass through rough and uneven terrains consisting of ancient icebergs, which will necessitate the use of long free spans with rock support. Deepwater seabed installation equipment will be used for construction of the pipeline.
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Ramboll was responsible for carrying out the front end engineering and design (FEED) study for the project. The company was also responsible for quantitative risk analysis and preparation of the environmental impact assessment. Nemo was the subcontractor for the FEED study.
Ramboll was also awarded the contract for the detailed design of the pipeline.
In February 2013, Statoil awarded three contracts worth Nkr 4bn ($694m) to three companies. Marubeni Itochu/JFE was awarded a fabrication contract worth Nrk 2.4bn ($416m), which includes an option for the spur line to the Kristin platform.
The second company was Wasco, which was awarded the coating contract worth Nrk 1.2bn ($208m). The scope of the contract includes the construction of a new production facility in Mo i Rana in northern Norway. Wasco will utilise a number of local subcontractors in Norway for applying concrete coating for the pipeline at the new facility.
Allseas won the Nrk 750m ($130m) contract for the pipe laying.