Gas pipeline to continental Europe

person By Kristin Øye Gjerde and Gunleiv Hadland, Norwegian Petroleum Museum
When production started from Statfjord A in 1979, oil was loaded into shuttle tankers on the field for transport to land while associated gas was initially flared. Gas injection back into the reservoir started in June 1980.
But it was already clear at the time that a new transport system for gas had to be built and brought into operation by 1985-86. Continued injection might otherwise damage the structure of the reservoir andreduce oil recovery.
— The processing plant at Kårstø. Illustration: Jan Ulriksen
© Norsk Oljemuseum

In a letter to the Norwegian licensees in Statfjord (the Statoil/Mobil group) in April 1980, the Ministry of Petroleum and Energy (MPE) made it clear that landing gas in Norway had to be studied as thoroughly as options involving landfalls in other countries.[REMOVE]Fotnote: Norvik 1981, p 5. Where such a pipeline might come ashore on the Norwegian coast was one of the questions to be considered.

Statoil was in favour of Kårstø north of Stavanger, while Norsk Hydro wanted Mongstad near Bergen in order to strengthen existing industrial development there.[REMOVE]Fotnote: Ibid, p 6. The technical and financial aspects of both options were studied, but the MPE opted ultimately to support Kårstø. A crucial consideration was that the Statoil/Mobil group should bear financial responsibility for the project. [REMOVE]Fotnote: Stafsnes 1984, p 100.

When the Storting (parliament) considered the issue on 10 June 1981, 94 representatives backed Kårstø while 54 were in favour of Mongstad. By the time this vote took place, the economics of laying pipelines across the deepwater Norwegian Trench had become better than they were two years earlier.

A tripling in oil prices following the Iranian revolution of 1979 had made a positive impact on financial margins. Nobody doubted any longer that Statfjord would be a profitable field. At the same time, it was feared that the British would become a monopoly buyer of Norwegian gas if supplies from Statfjord as well as Frigg were landed in theUK.[REMOVE]Fotnote: Gjerde and Ryggvik 2009, p 170. A landfall in continental Europe would allay such concerns.

The Statoil/Mobil group sent a landing application for gas from Statfjord to the MPE in December 1980, together with studies of the landfall options. For the first time in Norwegian oil history, this application met the requirement that petroleum from the country’s continental shelf should be landed in Norway.

Gas from Heimdal and the Gullfaks field were also to be accommodated by the same transport system, which would be owned and run by a pipeline company with Statoil as operator. [REMOVE]Fotnote: Stafsnes 1984, pp 97-99.

fordeling mellom norge og storbritannia, forsidebilde, historie, Gass via Kårstø til kontinentet,
British and Norwegian Continental Shelf

This solution did not apply to the whole of Statfjord. Roughly 15 per cent of the field lay in the UK sector, and the British licensees were not allowed to sell their gas to continental buyers. A separate gas pipeline was established to transport the British share.

Running from Statfjord B, this tied into the Northern Leg Gas Pipeline (NLGP) and became operational in 1985. The NLGP runs to Brent A, and the gas continues through the Far North Liquids and Associated Gas System (Flags) to the receiving terminal at St Fergus in Scotland. [REMOVE]Fotnote: Development of the UK Oil and Gas Resources 2001 .   Appendix 14 Offshore Oil and Gas Trunk and Interfield Pipelines.  Since 2007, Statfjord gas has been exported via the Tampen Link line, which ties into Flags.

The sales contract between the Statoil/Mobilgroup and the European buyers covering gas from Statfjord, Gullfaks and Heimdalwas signed on 1 September 1982. This was a “depletion” contract, involving thesale of all gas in the relevant fields. The buyers were a joint venture betweendistribution companies in West Germany, the Netherlands, France and Belgium. [REMOVE]Fotnote: The collaborating companies were Ruhrgas, BEB and Thyssengas, Dutch Gasunie, Gaz de France and Belgium’s Distrigaz.

This groupoffered to pay NOK 100 billion in 1982 money for gas from the three fieldsthroughout their producing life for about 30 years from 1986. The gas price obtainedby the Norwegian licensees – Statoil, Mobil, Conoco, Shell, Esso, Saga, AmeradaHess, Amoco and Texas Eastern – has been characterised as “the best everachieved”. Statoil was responsible for coordinating the Norwegian side in thenegotiations with the buyers.[REMOVE]Fotnote: Johnsen 1990, p 130-140.  (See the section on Selling the Statfjord gas .)

Statpipe – a technological milestone

Gass via Kårstø til kontinentet,
Arve Johnsen. Photo: Leif Berge/Equinor

Statoil’s first chief executive, Arve Johnsen, was asked in connection with the company’s 20th anniversary in 1992 to name the most important event during his 15 years at the helm. He responded that it was the Storting’s decision in 1981 which led in part to the Statpipe development:

“The Statpipe project was special because we did something everybody else thought would be extremely difficult – laying a pipeline across the Norwegian Trench in 380 metres of water. We also laid the basis for an infrastructure of gas pipelines from the NCS, which will have enormous significance for Norway and Statoil …” [REMOVE]Fotnote: Gjerde and Ryggvik 2009, pp 182-183.

Although Statpipe was actually only 300 metres down at its deepest, laying it represented a technological achievement. Unlike the pipelines from Ekofisk and Frigg, which ran directly over a relatively shallow and flat submarine plain to the British, Danish and German sectors, the whole 880 kilometres of Statpipe was laid on the Norwegian continental shelf. The challenge was not only the depth but also stretches of very broken seabed terrain.

Statpipe’s first leg ran from Statfjord to Kårstø, where the natural gas liquids (NGL) were separated out. The dry gas was sent back across the Trench to the Draupner S riser platform, where a spur from Heimdal to the north brought additional gas. Statpipe then continued to Ekofisk and tied into the existing pipeline to Emden in Germany. Pipelaying began in April 1983 with Statoil as operator. [REMOVE]Fotnote: A group of oil companies with interests in Heimdal, Gullfaks andStatfjord established the I/S Statpipe joint venture. This comprised Statoil 60per cent, Elf Aquitaine Norge 10 per cent, Norsk Hydro eight per cent, Mobilseven per cent, Esso five per cent, Norske Shell five per cent, Total MarineNorsk A/S three per cent and Saga Petroleum two per cent. Proposition no 102 tothe Storting (1980-81):  Ilandføring avgass fra Statfjordfeltet og Heimdalfeltet m v, p 56.

The pipelaying vessel was always followed bya diving support ship (DSV). Remotely operated vehicles (ROVs) were not well developed at that time, and divers were required to assist in such operations as measuring free spans along the route, laying sandbags and casting concrete.

Although most of the pipes were welded together on the laying vessels and laid out in their full length, a good deal of underwater welding was required in habitats under high pressure. However, the work was planned in such a way that welding was avoided in the deepest parts of the Trench. The deepest operational work dive was made to 245 metres on the edge of the Trench off the island of Utsira. [REMOVE]Fotnote: Gjerde and Ryggvik 2009, p 184.

Work dives to such depths had been the biggest obstacle to landing Frigg and Ekofisk petroleum in Norway. That barrier had been surmounted by 1983, with the development of saturation diving as a method. Experimental dives had also been conducted at Nutec in Bergen to verify that diving to 300 metres was acceptable. [REMOVE]Fotnote: Gjerde and Ryggvik 2009, pp 243-279.  (See the section on Statpipe diving .)

The opening of Statpipe in September 1985 represented a milestone in Norwegian oil history. An important technological barrier had been breached. The Trench was conquered.

This also marked the scaling of an important political and economic barrier for Norway. Greater direct national control had been secured over the oil industry, while conditions for industrialisation based on petroleum reserves were much improved. [REMOVE]Fotnote: Gjerde and Ryggvik 2009, p 189.

Sources

A North Sea gas gathering system . Joint report by British Gas Corporation and Mobil North Sea Limited, London, June 1980.
Gjerde, Kristin Øye and Helge Ryggvik: North Sea divers in Norway , 2009.
Helle, Egil (ed).  Olje og energi i ti år 1978-1988. Oslo,1987.
Hellem, Rolf. Oljen i norsk politikk . Oslo, 1974.
Johnsen, Arve. Norges evige rikdom. Oslo, 2008.
Nerheim, Gunnar. En gassnasjon blir til, Oslo, 1996 .
Norvik, Harald. Ilandføring av Statfjordgass og mulige oppdrag for norsk industri . Speech, NPC, 26 February 1981.
Stafsnes, Tor. Ilandføring av petroleum fra Statfjord: analyse av en iverksettingsprosess . Bergen, 1984.
Statoil. Statpipe – en Europavei for norsk gass . Stavanger, 1986.
Report no 90 to the Storting (1975-76): Om utbygging og ilandføring av petroleum fra Statfjord-feltet og om en samlerørledning for gass.
Proposition no 102 to the Storting (1980-81): Ilandføring av gass fra Statfjordfeltet og Heimdalfeltet mv.

Published October 29, 2019   •   Updated March 6, 2020
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