The Aasta Hansteen spar is a floating production storage and offloading (FPSO) unit for

natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

operated by

Equinor Equinor ASA (formerly Statoil and StatoilHydro) is a Norwegian state-owned multinational energy company headquartered in Stavanger. It is primarily a petroleum company, operating in 36 countries with additional investments in renewable energy. I ...

located 186 miles offshore in the Norwegian Sea. It is the first spar platform to be located on the Norwegian Continental Shelf (NCS). The Aasta Hansteen is named after Norwegian painter, writer and early feminist.

Design

The Aasta Hansteen platform is a truss spar type allowing

condensate Condensate may refer to: * The liquid phase produced by the condensation of steam or any other gas * The product of a chemical condensation reaction, other than water * Natural-gas condensate, in the natural gas industry * ''Condensate'' (album) ...

to be stored in the hull below sea level and offloaded to a shuttle tanker. The produced gas is exported to the shore with

steel catenary riser A steel catenary riser (SCR) is a common method of connecting a subsea pipeline to a deepwater floating or fixed oil production platform. SCRs are used to transfer fluids like oil, gas, injection water, etc. between the platforms and the pipelines. ...

s (SCR). The production risers are also SCRs, with these being the first time SCRs have been used in the Norwegian Sea. The spar hull was designed by

Technip Technip S.A. was a company that carried out project management, engineering and construction for the energy industry; in 2017 it completed a merger with FMC Technologies to form TechnipFMC. Its headquarters were in the 16th arrondissement of ...

, with the topsides being designed by CB&I, with both being fabricated by Hyundai Heavy Industries in South Korea before being transported to Norway for installation. Once on site it was partially submerged by filling ballast tanks to 177 m and anchored to the seabed, leaving only the top 21 m above the surface. The seabed moorings are primarily made of cut resistant polyester and steel chain. At a height of 198 m (of which 177 m will be submerged) and a diameter of 50 m it is the biggest spar platform hull ever built in terms of diameter and displacement. The Aasta Hansteen spar exports the

from the field through the Polarled pipeline to the

Nyhamna Nyhamna is a small peninsula on the northeast side of the island of Gossa in Aukra Municipality in Møre og Romsdal county, Norway. It is located along the Julsundet strait, about northeast of the village of Varhaugvika and northeast of the ...

processing plant on the Norwegian coast. The project cost approximately 37.5 billion NOK.

Transport and installation

The Aasta Hansteen spar was built on its side in the dry dock on barges. Once built it was floated off the barges and then floated onto the heavy transport ship ''

Dockwise Vanguard ''BOKA Vanguard'' (formerly ''Dockwise Vanguard'') is a semisubmersible heavy-lift ship owned and operated by Dockwise B.V. ''Dockwise Vanguard'' is the largest vessel of her type ever built, and is able to carry cargoes up to 110,000 tonnes. ''D ...

'' and shipped to a fjord near

Stord Stord is a municipality in Vestland county, Norway. It is located in the traditional district of Sunnhordland. Stord is sometimes called "Norway in miniature" since it has such a variety of landscapes: coastline, fjords, forests, agricultural ...

Western Norway Western Norway ( nb, Vestlandet, Vest-Norge; nn, Vest-Noreg) is the region along the Atlantic coast of southern Norway. It consists of the counties Rogaland, Vestland, and Møre og Romsdal. The region has no official or political-administrativ ...

. The spar was upended in the fjord, after which the topsides were installed using the floatover technique. It was then towed vertically to the Aasta Hansteen gas field 300 km off Bodø at the northwest coast of Norway. The spar will be moored north of the Arctic Circle using polyester moorings to the seabed 1200m below. The Aasta Hansteen began producing on 17 December 2018.

Aasta Hansteen gas field

Originally called the Luva gas field and later renamed after

Aasta Hansteen Aasta Hansteen, also known as Hasta Hanseen (born December 10, 1824 – April 13, 1908), was a Norwegian painter, writer, and early feminist. Life and career Aasta Hansteen was born in Christiania, modern day Oslo, the daughter of Christopher ...

, it was discovered in 1997 approximately 300 km off the coast of Norway. During start up of the platform, the production from the surrounding Luva, Haklang and Snefrid gas fields will be exported to the platform. Future fields already discovered are planned to be tied back to the Aasta Hansteen platform through SCRs. Future expansion of additional risers and topsides facility are built-in in the design of the platform. The field is located north of the Arctic Circle, and is subject to perpetual darkness and sub-zero temperatures in the winter months.

References

{{Portal, Norway, Energy Oil platforms off Norway 2018 establishments in Norway