The occupational health service on Statfjord in 2010

person by Trude Meland, Norwegian Petroleum Museum
With Statfjord far from land and the nearest hospital an hour away by helicopter, it has been important to maintain a good and acceptable occupational health service (OHS) on the field.
— The hospital at Statfjord B. Here, they have direct contact with health personnel on land via high-tech devices. Photo: Shadé Barka Martins/Norwegian Petroleum Museum
© Norsk Oljemuseum

The operator, initially Mobil and subsequently Statoil, has always been responsible for the health and safety of everyone on the platforms. It has accordingly stationed nurses there around the clock as part of an OHS supported by the organisation on land.

Pursuant to section 30 of Norway’s 1977 Working Environment Act, the purpose of the OHS was to contribute to creating and maintaining safe and sound working conditions and to look after the health of employees both on land and offshore.[REMOVE]Fotnote: This represented a big change from the traditional goal of medical services, which had been to support and assist people suffering from pain, worry or disability, and to nurse them in the best possible way so that they could return to work and the community. The idea of preventive work acquired a strong position through the Working Environment Act.

Bedriftshelsetjenesten 2010,
Sykepleier Else-Gunn Dybvik t.v. undersøker telegrafist Inger Helen Viken på Statfjord C. Foto: Leif Berge/Equinor

These goals laid the basis for Mobil’s planning of health provision for Statfjord.[REMOVE]Fotnote: Statfjord was the only Norwegian field operated by Mobil, and the whole company in Norway was structured around what was to happen there. Internal memos reveal that its OHS was to offer the most satisfactory possible medical services to workers on the installations, and to help build up a good emergency response organisation on the field.

It was to survey and monitor the working environment and worker health, and to advise employees and employers on health risks and on measures to prevent illness and promote good health. The service was also to contribute to diagnosis, treatment and rehabilitation of people suffering from illness or injury, and to provide occupational health and hygiene advice in the workplace.[REMOVE]Fotnote: Occupational health and hygiene covers the identification of health risks at work and the science of preventing illness and accidents in the workplace. Work on preventing injuries and promoting health covers not only microorganisms but also chemical and physical hazards. Knut Jørgen Jørgensen’s archive.

The offshore nurse

Bedriftshelsetjenesten 2010,
Sykepleier Gyro Mauland ombord på en av boligplattformene som lå ved siden av Statfjord A, som troner i bakgrunnen. Foto:Leif Berge/Equinor

The offshore nurses provide the front line of the OHS on Statfjord. They are there to help everyone on the field, and not just Statoil employees. Their work primarily covers three areas. One is the provision of a general medical service, which involves acting in the same way as a family doctor on land. They also provide acute medical help. Finally, they form part of the OHS – when the company brings in employees for follow-up and supervision, as in cases where the nurse learns that a person has been exposed to noise or chemicals.

The nurse is required to conduct regular safety inspections, frequent checks of hygienic conditions, monitoring and sampling of drinking water, and maintenance and inspection of first-aid gear, eye washing stations and medical equipment.
Their job also involves keeping an eye on and reporting undesirable or unhealthy conditions in the working environment. That includes measuring noise, light and pollution levels in collaboration with the occupational hygienist.

Offshore nurses require nursing qualifications and broad experience, and usually have additional training in acute, hyperbaric (diving) and disaster-response medicine. Most are also certified to perform anaesthesia and have studied occupational health.

All nurses employed by Statoil must take a 40-hour basic first-aid course, and a new programme has also been developed at the Stavanger Acute Medicine Foundation for Education and Research (Safer).[REMOVE]Fotnote: Established by the University of Stavanger, Stavanger University Hospital and the Lærdal company. This fully equipped facility offers simulator training on medical issues. The first-aid team offshore also undergo simulator testing.

Under the new operations model introduced after Statoil merged with Hydro oil and energy, the offshore nurses have been given the title of health, safety and environmental (HSE) coordinators. Their job is largely the same, but they have taken over a number of functions from the safety department.

The former safety inspectors, leaders and department have virtually disappeared from the platforms, and safe operation has become a line management responsibility. The nurses are involved in the conduct of safe job analyses (SJAs) and in checking work permits.

Being the sole nurse on a Statfjord platform is a big responsibility, so clear protocols and procedures have been developed. These are constantly evaluated and amended as required. The protocols developed for medical conditions and injuries describe how far a nurse should go in examination and treatment. In specified cases, they can start treatment and administer medication without contacting a doctor on land.

Bedriftshelsetjenesten 2010,

When action is not authorised by the protocol, the duty doctor must be contacted and the latter becomes responsible for treatment from the moment they receive the phone call and the nurse has explained what has and has not been done. Until then, the nurse is responsible. The procedures describe what medication can be administered and in what doses. Procedures and protocols are developed in collaboration with the acute medicine section at Bergen’s Haukeland Hospital. The latter also receives the bulk of the patients.

When a course of treatment starts on a platform, it is accordingly one which the hospital itself has defined as the standard. If the patient is to be treated at another hospital, Haukeland communicates with it to explain the procedures implemented.[REMOVE]Fotnote: Interview with Arne Evensen by Trude Meland, Norwegian Petroleum Museum, 7 July 2011.
Each offshore installation has a health office/sick bay equipped with medical equipment and medication to deal with more everyday problems as well as with acute and life-threatening conditions.

Devices are available for resuscitation, treating shock, burns and heart conditions, and electrocardiography (ECG), along with medications for sedating patients.
Telemedicine systems have been installed in recent years on all three Statfjord platforms so that doctors on land can see and speak directly with the patient. They can thereby establish a closer dialogue with offshore nurses and patients, enabling them to make faster and more accurate diagnoses. Acute cases which previously had to be described over the phone can now be shown on the display.[REMOVE]Fotnote: Origo, April 2010.

Duty doctors

A 24-hour duty doctor service on land is available at all times to provide medical advice and guidance for health personnel on the installations. Mobil started by recruiting Bergen-based doctors in private practice as duty physicians for Statfjord. After Statoil took over as operator, the service was transferred to doctors employed by the company. These were then not only duty doctors but also had OHS responsibility for offshore employees.

Until Statoil merged with Hydro oil and energy, duty doctors employed by one of these two companies would cover for those of the other when required.
The duty doctor scheme for Statfjord has been assigned today to Offshore Health Service in Bergen, and the agreement extended to telemedicine equipment in order to strengthen the OHS on the field. Duty doctors have their own office and surgery at Statoil’s Sandslihaugen premises outside Bergen.


Bedriftshelsetjenesten 2010,
Sykepleier Odd Abrahamsen utfører førstehjelp i sykestuen på Statfjord C. Foto: Øyvind Hagen/Equinor

The offshore nurses report administratively today to the platform manager on the relevant installation, but for personnel and professional matters they report through the line management to the company medical officer on land.
The OHS in Statoil on land includes a chief occupational health physician reporting to the corporate management, and a medical officer responsible for Statfjord who sits in Stavanger.[REMOVE]Fotnote: The location of the responsible medical officer varies from field to field. The one for Gullfaks and Oseberg, for example, sits in Bergen. In addition comes a manager for medical treatment services, who is responsible for defining medical standards and determining the content of the medical protocols.

During the Mobil era, Statfjord had its own OHS. This was moved after the transfer of the operatorship to the Statfjord division in Statoil and later merged with the Gullfaks division to become the OHS Bergen. The latter was incorporated from 1 May 1989 in an organisation to serve Gullfaks, Veslefrikk and Statfjord as well as all Statoil employees in the Bergen area. Its primary goal was to pursue preventive work – combating occupational ill health and injuries in the widest sense.[REMOVE]Fotnote: Log of 4 June 1989, p 6. Knut Jørgen Jørgensen’s archive.
This was the structure almost until the merger with Hydro oil and energy. Today, the whole OHS in Statoil is concentrated in a department in Stavanger with a responsible medical officer for each field.

Bedriftshelsetjenesten 2010
To av sykepleierne på Statfjord C, Svein Stalheim t.v og Jarle Offerdal i forgrunnen, demonstrerer avansert medisinteknisk utstyr for oljemuseets utsendte medarbeider Gunleiv Hadland. Foto: Jan A. Tjemsland/Norsk Oljemuseum

The OHS on land has recruited various specialists, such as occupational hygienists who carry out surveys and measurements, and physiotherapists involved in preventive health work. They are particularly concerned with ergonomic conditions in the working environment, both offshore and on land.
Work on ergonomics began as early as the Mobil era. New facilities were devised in cooperation with physiotherapists and the health office to increase work accessibility and ease of use, and to make work operations more ergonomically appropriate. These included the development of skids and crane hooks as well as a completely new type of crane cabin.

Offshore first-aid team

The nurses are responsible for putting together first-aid teams on the respective platforms. Although many offshore workers are not keen to participate in such emergency preparedness measures, everyone on the platform can be selected to take part.

This is a job offshore personnel cannot refuse. They are supposed to know basic first-aid, and to be familiar with the platform. Employees are used as response personnel in the event of fires, explosions, uncontrolled gas and oil leaks, and so forth.

Published November 14, 2019   •   Updated May 15, 2020
© Norsk Oljemuseum
close Close

The Statfjord B letter

person by Trude Meland, Norwegian Petroleum Museum
Preparations for building the Statfjord B platform were well under way in the autumn of 1976. But the Norwegian Petroleum Directorate, as the regulator responsible for offshore safety, had its own views on the project. It expressed these in a letter sent to operator Mobil on 11 November 1976, which came to change all the plans.
— Norway's most expensive letter, it was called, the letter that instructed the Statoil/Mobil group to change the structure of Statfjord B.
© Norsk Oljemuseum

At that time, contract negotiations had been pursued with Norwegian Contractors on building a four-shaft Condeep gravity base structure (GBS). They were at the point where a letter of intent was ready.

The recently established Norwegian Petroleum Consultants (NPC) joint venture had also signed a contract on project management and engineering design for Statfjord B. Read more about NPC in the section on Statfjord B – the first plan.

While the contract for building the platform topside and mechanical outfitting of the GBS shafts had yet to be awarded, an option agreement had been secured with the Aker group.

So all the main contracts for the project appeared to have been put in place. The Storting (parliament) had also approved phase II of the development plan in June 1976, and most people assumed that it was simply a case of starting to build.

Until the NPD letter arrived

The Vogt commission

The Statfjord B topside. Photo: Mobil Exploration Norway Inc./Norwegian Petroleum Museum

New safety regulations for the Norwegian offshore industry had been adopted on 9 July that year. A key issue for Statfjord B and the field licensees was the introduction of a more restrictive attitude towards simultaneous drilling and production combined with living quarters on a single integrated platform.

The new rules had been developed by a commission of inquiry appointed by the government as early as 22 May 1970 with a mandate to propose regulations for the safety of production and storage facilities on the seabed and of exploiting petroleum deposits.[REMOVE]Fotnote: Norsk Oljerevy. (1976). no 2. Kontroll med sikkerheten fordelt på ni instanser. 

Work in the commission progressed slowly and its chair, Jens Evensen, asked to be relieved. He was replaced in November 1972 by director general Lars Oftedal Broch, who was replaced in his turn during May 1974 by Nils Vogt from the NPD.

The latter gave his name to the commission’s report, which was submitted to the Ministry of Industry on 12 July 1975. It was then circulated for consultation to affected companies and institutions.[REMOVE]Fotnote: Hanisch, T., Nerheim, G., & Norsk petroleumsforening. (1992). Fra vantro til overmot? (Vol. 1). Oslo: Leseselskapet: 324.

Adopted by royal decree of 9 July 1976, the new safety regulations were based on the recommendations of the Vogt commission and on comments received in the consultation process. One provision of the decree was that the NPD would bear primary responsibility for supervising fixed offshore installations.

Safety issues on Statfjord were viewed by the directorate through the prism of the new regulations. It kept the industry ministry informed about its work, and wrote the following in a letter dated 7 July 1976:

“Given the work being done on safety conditions, it has been found necessary to adopt a more restrictive attitude to those concepts which are based on combined drilling and production, where the living quarters are also placed on the same platform. The main intentions of the Vogt commission’s recommendations run counter to both combined activity and the above-mentioned placement of living quarters … The NPD would emphasise that combined drilling and production will only be accepted following individual analyses and assessments. The same applies to living quarters which it is proposed to place on a drilling/production platform. No final choice of concept has been made for Statfjord B, so no specific safety analysis has been submitted. Comments from the NPD will accordingly have to wait until it the actual conditions have been presented.”[REMOVE]Fotnote: Norsk Oljerevy.

In other words, the ministry had been informed of the NPD’s work and of its scepticism about the plans for Statfjord B. As the letter indicated, the regulator could not adopt a final position until the Statfjord Unit Operating Committee (SUOC) had approved the concept chosen for the B platform in late August 1976. Only then could the NPD conduct its own safety analysis.

It was called Norway's most expensive letter. The letter instructed the Statoil/Mobil group to change the structure of Statfjord B.

The results of the latter were presented to the Statfjord licensees in the above-mentioned letter of 11 November 1976, where the NPD questioned the safety of an integrated platform and ordered the construction of a separate quarters platform:

“The NPD is currently assessing the concept for Statfjord B on the basis of a general evaluation of the safety rules on the field in the light of the new regulations (royal decree of 9.7.76)

“Statfjord B is expected to involve:

  • particularly complex and extensive production facilities concentrated on a single platform
  • a large number of producing wells with high capacity, along with water and gas injection
  • permanent living quarters for 200 occupants, which will be used by 400 people during the construction phase and possibly the drilling phase
  • possible simultaneous drilling and production.

“The total risk is characterised by the contributions from each of the activities and processes which include the examples given above. The NPD’s assessment is that the total risk associated with these conditions lies at too high a level.

“In the NPD’s view, the best way to reduce the total risk would be to reduce the number of people who are present on the platform at any given time. The NPD has accordingly concluded that a separate quarters platform connected to Statfjord B should be built.”

This safety assessment was not confined to Statfjord B. Questions were also posed about the A platform, construction of which was far advanced at the time. It was due to be towed out to the field in six months.

“The considerations mentioned above also apply to Statfjord A, if to a somewhat lesser degree. The NPD would accordingly, on the basis of the provisions in the royal decree of 9.7.76, request that the company undertakes a new overall assessment of safety conditions [on this installation] in relation to the planned drilling and production programme, with particular attention paid to the accommodation issue.”

This letter was signed by Gunnar Hellesen, chair of the NPD board, and director general Fredrik Hagemann.

New concepts proposed

Statfjord B was intended to be a virtual copy of the A platform, but with four support shafts instead of three. The process facilities would be equally large and complex, with a production capacity of 300 000 barrels per day, and the 200-berth quarters module was to be installed on the platform.

It was the last feature in particular that the NPD wished to prevent. The regulator took the view that cutting the number of people on the platform at any given time would reduce the overall risk.

As the letter indicates, the desirable solution was seen to be the construction of two platforms – one for production and drilling, and the other for accommodation. The NPD also emphasised the need for overall safety thinking, and wanted a separate safety study carried out before detailed planning began.

Statoil and Mobil expressed surprise at the letter, and claimed they had not heard that such assessments were being made. Arve Johnsen, then Statoil’s chief executive, described his reaction to the letter in his book Utfordringen (The Challenge): “As chief executive of Statoil, I received many kinds of letters … I have forgotten most of them, but I will remember one to my dying day … It sent a shock wave through the licensees in the Statfjord group.”[REMOVE]Fotnote: Johnsen, A. (1988). Utfordringen : Statoil-år. Oslo: Gyldendal: 202.

It might seem incomprehensible that the partners had failed to see this coming. They had long been aware that the NPD was looking at problems associated with simultaneous drilling and production, and the Vogt commission’s report had been through a consultation process. Comments in the latter as well as the report itself formed the basis for the new safety regulations.

Adopted in June, four months before the letter was despatched, the regulations specified that simultaneous drilling and production was prohibited without special permission. This should have sent certain signals that the plans for Statfjord B might be more difficult to implement than Mobil and Statoil thought.

As late as 12 October, section head Harald Ynnesdal had explained the NPD’s view on the issue in a speech he gave in Kristiansand:

“The new platform types are particularly complex and difficult to assess from a safety perspective with regard to these combined activities. As far as possible, fields should be planned with separate quarters platforms. The production platforms could then, with their combined activities, be assessed purely as industrial plants.

“In an assessment of simultaneous drilling and production in the Statfjord project, for example, the problem would have been much simpler if separate quarters platforms had been adopted. The cost of such platforms would have had little effect on profitability for this project, but would have meant a great deal for overall safety and the desire for an early start to production.”[REMOVE]Fotnote: Norsk Oljerevy. (1976). no 9. Statfjord – planer og virkelighet. On the basis of this letter, an extraordinary meeting of the SUOC was called on 26 November. It decided that all activities related to Statfjord B would be halted. The project would have to be re-evaluated, and extensive conceptual studies were to be carried out for every option from one to three platforms.

" two giants become four little ones" Headline from Aftenposten 25. juni 1977

A meeting of the Statfjord field engineering committee (SFEC) – the technical project team – took place in January 1977. A 35-strong sub-committee was appointed to study and assess various conceptual solutions for Statfjord B, and came up with 39 variants for consideration.

When the SUOC met again on 18 March, Statoil expressed concern at the progress made. The project had a tight timetable, and order books at the Norwegian shipyards were empty. To speed up the process, the company proposed a separate drilling platform linked by a bridge to a combined production and quarters unit.

A drilling platform supported on a steel jacket, for instance, would be relatively cheap to build and could be ready for tow-out as early as 1979. Drilling of production wells could start as soon as the platform was in place, and continue while the associated production and quarters facility was under construction.

As soon as the latter had been installed, oil and gas could thereby begin.[REMOVE]Fotnote: Norsk Oljerevy. (1977). no 5. Industrien må fortsatt vente på Statfjord B.  This meant in turn that the original schedule set in the field development plan could be met.

Mobil and Saga were strongly opposed to this plan, but did not have enough votes to block it. Their interests added up to only 25 per cent, while resolutions in the SUOC needed 70 per cent support. The Statoil proposal was thereby adopted – against the operator’s vote.

Esso also proposed its own solution at the meeting, comprising an integrated production, drilling and quarters (PDQ) platform but with processing capacity halved to 150 000 barrels per day. This facility would be simpler, since only one process train was required rather than the original two, and overall safety would be improved.

Mobil supported the Esso proposal. The two companies were uncompromising in their opposition to two platforms, and maintained that this would provide no safety benefit. A factor in their assessment was the poor seabed soil conditions on Statfjord, which meant that installing two platforms so close to each other and linked by a bridge carrying high-pressure pipelines would pose a safety risk.

The thought of the substantial capital investment required for two platforms also worried the operator. On the other hand, experience from other North Sea projects suggested that a capacity of 150 000 barrels per day would be sufficient. Such a solution would reduce construction costs by simplifying the platform, and production could also start earlier.


A further meeting of the SUOC was held on 28 April, when Mobil proposed an integrated platform with a single process train and an average capacity of 180 000 barrels per producing day. This size had been chosen in the hope of avoiding a separate quarters platform.

The change to the original concept was so large that a completely new field development plan might have to be produced. According to the proposals approved the Storting in the summer of 1976, three platforms with a combined capacity of 900 000 barrels per day were to be installed.

Reducing the size of the process facilities on each platform would either require more structures to maintain the planned output, or a slower pace of production.[REMOVE]Fotnote: Norsk Oljerevy. (1977). no 5. Industrien må fortsatt vente på Statfjord B.  Fresh consideration by the Storting could delay the project further.

At the same time, Mobil vetoed a separate quarters platform.[REMOVE]Fotnote: Moe, J. (1980). Kostnadsanalysen norsk kontinentalsokkel : Rapport fra styringsgruppen oppnevnt ved kongelig resolusjon av 16. mars 1979 : Rapporten avgitt til Olje- og energidepartementet 29. april 1980 : 2 : Utbyggingsprosjektene på norsk sokkel (Vol. 2). Oslo: [Olje- og energidepartementet]. With strong support from Esso, the operator noted that it could not accept a solution which complied with the NPD’s principle that drilling and production should not take place simultaneously on the same installation.

" Platform living quarter confrontation" Headline from Aftenbladet 28. juni 1977

Clear instructions had been sent from Mobil’s head office in New York that a compromise solution which would involve an acceptance of the NPD principle was out of the question. It feared that conceding this demand from the Norwegian regulator could lead to similar requirements on other continental shelves, which would have major consequences for both Mobil and its fellow oil companies.

A telex from New York emphasised that, the way things looked, concrete platforms on the scale of Statfjord A had outplayed their role on this field. Mobil was willing to renounce the operatorship for Statfjord B if a two-platform solution was adopted. This attitude took Statoil and the Norwegian government by surprise.[REMOVE]Fotnote: Norsk Oljerevy. (1977). no 5. Industrien må fortsatt vente på Statfjord B. 

Statoil explored the possibility of another operator, but none of the other partners was willing to take on the role without a reallocation of licence interests. Mobil and Esso had staked their prestige on the issue, and they finally managed to convince Statoil of the technical problems posed by a two-platform solution. The argument that this could affect later developments in deeper water was central to the Norwegian company’s change of mind.

The discussion on one or more platforms and the studies of various concepts were paralleled with the presentation of new seismic data for the field. These cut its estimated oil reserves from 3.9 billion barrels – equivalent to 527 million tonnes – to 3.2 billion or 432 million tonnes. That reduced the need for two process trains on Statfjord B.


On 5 August, the SUOC approved plans for a platform with the capacity to process 180 000 barrels per day. It was resolved on 29 November to apply to the NPD for permission to build such a structure. The application, accompanied by a separate safety study, was submitted on 1 December.

Plans now called for Statfjord B to be installed in 149 metres of water at the southern end of the field. Seabed conditions were poorer there than over the rest of Statfjord, and the base area of the GBS accordingly had to be increased.

While Statfjord A had 19 cells, the B version would have 24. Planned topside space would expand correspondingly, from 5 200 square metres to 7 800. The platform would still have four shafts even though only one process train was to be installed. With the fourth shaft reserved for risers, space was freed up in the others.

Additional safety barriers were introduced by the decision to make the decks and modules open, reducing the danger of an explosion and possible damage from such an incident. The various functions would also be positioned in such a way that no hazardous operations were close to or beneath the living quarters. And the quarters modules would be protected by an additional fire wall. These plans were approved by the NPD on 19 December.

The project had been delayed by a year and incurred substantial costs through a number of conceptual studies and reports. According to Henrik Ager-Hanssen, deputy chief executive of Statoil, the letter from the NPD was the most expensive in Norwegian history and cost the project NOK 25 million per word.

Viewed from a different perspective, former Statoil staffer Bjørn Vidar Lerøen has noted that oil prices reached record levels over the next few years. That meant the letter became one of Norway’s most profitable.[REMOVE]Fotnote: Lerøen, B., Gooderham, R., & Statoil. (2002). Drops of black gold : Statoil 1972-2002. Stavanger: Statoil: 149.

Published May 23, 2018   •   Updated May 5, 2020
© Norsk Oljemuseum
close Close

Gas pipeline agreements

person By Håkon Lavik, former Statoil employee
The sale of gas from Statfjord made it necessary to connect the platforms with flowlines to gather gas for export via the Statpipe system. Oil flowlines also linked the platforms, but these had been installed as part of the field development.
— Statfjord field with associated gas pipelines. Source: Storting Report 39 1984–85
© Norsk Oljemuseum

A separate project, the Statfjord intrafield pipeline system (Sips), was established to engineer and install the gas lines. Once the work had been completed, Sips was taken over, owned and operated by the Statfjord Unit. In formal terms, Sips
forms part of the Statfjord Facilities – in other words, all the platforms, flowlines, wells and so forth which have been developed to operate the field.

Since the British licensees in Statfjord were not allowed to sell their gas to continental Europe, a separate UK Gas Offtake pipeline was laid as part of Sips from Statfjord B to the UK side of the boundary. There it tied into the Northern Leg Gas Pipeline (NLGP), a gas gathering line for fields north of Brent. The Statfjord Unit owns that part of the UK Gas Offtake line which lies within its boundaries, while the British licensees own the section to the west, including the NLGP tie-in. The UK government demanded the inclusion of a non-return valve in this line, so that British gas could not be conducted to Statfjord B.

This line was regulated by the Agreement for Installation and Tie-in of the UK Pipeline to the Statfjord B Platform and to the Northern Leg Gas Pipeline , which entered into on 1 February 1983. The UK Statfjord Gas Offtake Operating Services between Mobil Exploration Norway Inc and Conoco (UK) Ltd service agreement was also signed on 27 September 1985. A gas pipeline was laid from Gullfaks A to Statfjord C under a separate Agreement for Tie-in and Operation of the Gullfaks Pipeline to the Statfjord C Platform between the two sets of licensees,   dated 27 September 1984.

Gas from Gullfaks was carried via Sips before entering Statpipe until the end of the 1990s, when Gullfaks acquired a new tie-in to Statpipe south of Statfjord. Gas transit via Statfjord accordingly terminated, but the pipeline from Gullfaks is still intact and usable and the tie-in agreement remains operative.

Statpipe tie-in

Statpipe map from Gullfaks brochure 1984. Illustration: Equinor

Although the Statpipe system starts from the field, it does not form part of the Statfjord Unit. A separate pipeline and transport company was established after the gas from Statfjord, Gullfaks and Heimdal had been sold in 1982.

The purpose of this joint venture was to install pipelines and build the Kårstø processing plant north of Stavanger in order to export gas from the Norwegian continental shelf (NCS) via Ekofisk to Emden in Germany. Where Statfjord was concerned, this meant that a contract was signed on 12 July 1984 between the Statfjord Unit and Statpipe concerning the tie-in of the pipeline to Statfjord and its subsequent operation.

 Statfjord B serves as the starting point for Statpipe, and the valve system on the seabed is operated from that platform. But it was Statfjord C, via Sips, which was responsible for maintaining pump pressure in the pipeline and ensuring that the gas flowed to Kårstø.
Statpipe later became part of the Gassled joint venture, and the section from Statfjord to Kårstø now lies in Gassled’s tariff zone 1. In connection with the Statfjord late life (SFLL) project, the connection between Sips and Gassled was severed in 2007. Statfjord B now provides the connection with Gassled.

Statpipe-Statfjord transportation agreement

Dated 30 September 1985, this contract secured transport rights in Statpipe for the Norwegian share licensees in Statfjord. The agreement still exists in principle, but was converted on 1 January 2003 to individual contracts for each licensee following the adoption of the EU’s gas directive. Each company accordingly has its own transport agreement. That was also the original position, but based on a single contract.
Similarly, each of the licensees in the Norwegian share of Statfjord had separate sales agreements for its proportion of the gas with the buyer consortium in continental Europe. These contracts were terminated in 2007, since the volume sold under them was deemed to have been delivered. Statfjord gas, including output from the SFLL project, is sold today to the UK.

Tampen Link

Tampen Link. Illustration: Equinor

As part of SFLL, the decision was taken to lay a new pipeline from Statfjord to tie into the Far North Liquids and Associated Gas System (Flags) in the UK North Sea. The latter runs from Brent to St Fergus in Scotland.
Tampen Link is a separate company operated by Gassled. Dated 22 February 2005, the contract related to Statfjord has a long name: Agreement Between the Tampen Link Joint Venture and the Statfjord Group for the Installation and Tie-in of the Tampen Link Transportation Facilities to the Statfjord Facilities and the Operation of the Tampen Link Statfjord Facilities and the Operation of the Tampen Link Statfjord Facilities and the Transit Services at the Statfjord Facilities.
This agreement makes it possible to transport gas from Statfjord directly to Flags and the UK, and from other fields in transit via Statfjord to the same destination.

Crossing agreements

Since Statfjord is a hub for oil and gas exports from the northern North Sea, a number of pipelines large and small have been laid. Where these cross over each other, a crossing agreement has to be established. You cannot simply lay your pipeline over one belonging to somebody else and possibly cause damage. This must be regulated.

The following agreements have been established so far:

  • Crossing of the Statfjord B Pipeline and the Statfjord Control Umbilical by the Penguin Pipelines and Cable , dated 22 March 2002. (Penguin is a small UK field tied back to Brent.)
  • Pipeline Crossing and Laying Agreement Between Statfjord Unit and Sygna Unit , dated 14 April 2000.
  • Pipeline Crossing Agreement Between Statfjord East and Statfjord North Flank , dated 1 April 1999. (the north flank is the northernmost part of Statfjord, developed with subsea wells).
  • Pipeline Crossing Agreement Between Tampen Link and Statfjord Unit , dated 20 November 2006.

Published October 30, 2019   •   Updated February 18, 2020
© Norsk Oljemuseum
close Close

Changing the operator

person By Håkon Lavik, former Statoil employee
Transferring the Statfjord operatorship from Mobil to Statoil ranks as one of the biggest controversies in Norwegian oil policy. The 1973 licence allowed a change of operator to be requested 10 years after a discovery was declared commercial, and Statoil asked to exercise this right in 1984. Mobil was opposed, and felt it would suffer a huge loss of prestige from such a transfer.
— Statoil takes over operator responsibility from Mobil. Martin Bekkeheien and Mike Smith pictured together with a model of Statfjord A. Photo: Leif Berge/Equinor
© Norsk Oljemuseum

The US major at least wanted a visible compensation for the loss of the operatorship. It asked first to become operator for block 30/6, which proved to contain the Oseberg field.

When that failed, Mobil “declared war” on Statoil and began to fight to retain the operator role. It argued that the state oil company had gone behind its back by securing the exploration operatorship for 30/6.

Although Mobil secured an interest in the block, it felt that this was not enough. Moreover, the operatorship for 30/6 was transferred from Statoil to Norsk Hydro in 1982 – Norway’s first political decision on such a change.

Mobil next sought to secure the operatorship for block 34/7, where Snorre, Vigdis, Tordis and Borg were to be discovered, but again without success. Norway’s Saga Petroleum became the operator – and Mobil was not even offered a holding in the block.

The Statfjord operatorship became a hot political issue during the early 1980s. That was because it involved Statoil and the size of that company, and because “clipping Statoil’s wings” had been a manifesto commitment for the Conservative Party in the 1981 general election. That promise in turn led eventually to the creation of the state’s direct financial interest (SDFI) in 1984, in effect from 1985.

Before that, however, the operator issue had to all intents and purposes been settled in 1983, with a formal decision in 1984. The question was considered by the standing committee on industry of the Storting (parliament) in 1983 in connection with the annual Statoil report to the committee.

Both Mobil and Statoil were asked to submit their arguments. The former decided to devote its time to rubbishing the state oil company. That annoyed so many members of the committee that its chair, Reidar Due, noted afterwards that a majority already existed for the fastest possible change of operatorship.

Kåre Kristiansen. Photo: Stortingsarkivet/Scanpix

Kåre Kristiansen from the Christian Democratic Party, who became petroleum and energy minister in 1983, was opposed to a transfer. So were prime minister Kåre Willoch and finance minister Rolf Presthus, both Conservatives.

However, a majority recommendation from the industry committee in favour of a transfer was backed by members of the Centre and Christian Democratic parties. Since these were both part of the governing centre-right coalition, this act was political dynamite.

The outcome was that Willoch himself contacted the committee and had the recommendation revised before the document was submitted to the Storting’s presidium. This meant in practice that Due and the other members of the coalition party – including Arnljot Norwich and Svein Alsaker – agreed to postpone the issue for a year. Kristiansen failed to grasp that.

When the issue came up again in the autumn of 1984, the fronts had consolidated. Mobil was battling desperately to retain the operatorship, while Statoil fought just as hard to secure it.

In an attempt to resolve the question without bringing down the coalition, local government minister Arne Rettedal asked the two companies to agree on a collaboration agreement.

Such a deal was actually drawn up, but rejected the following day by Mobil before it could be submitted to Rettedal and Kristiansen. This was because the US company had received clear signals from Kristiansen that a decision on the operatorship would be postponed, perhaps for a decade.

Before Mobil rejected the agreement, it asked Kristiansen whether he stood by his word. He did. But things fell apart when the deal was turned down. The government could no longer prevaricate, and the message from the industry committee was once again clear. Both the Centre and Christian Democratic Parties would support Labour and ensure a majority for a change.

If the issue was not resolved that autumn, the government would be defeated and might fall apart or have to resign. Faced with that prospect, the coalition resolved unanimously on the following day that the operatorship would be transferred.

The Storting followed up with a decision in December 1984, and the transfer was implemented painlessly during 1986. Statoil became operator on 1 January 1987. The transfer decision marked the end of the last major Norwegian political controversy over Statfjord.

Published October 30, 2019   •   Updated February 14, 2020
© Norsk Oljemuseum
close Close

Building the concrete GBS

person by Trude Meland, Norwegian Petroleum Museum
Statfjord B represented a new generation of Condeep gravity base structures (GBS). When built, it was the world’s largest human construction in history and much bigger than the Statfjord A concrete support structure.
— Statfjord B's concrete gravity base structure (GBS) under construction in 1979. Photo: Geir Ivar Jørgensen/Norwegian Petroleum Museum
© Norsk Oljemuseum
Bygging av betongunderstellet,
The Statfjord B GBS in Gandsfjorden. Foto: Leif Berge/Equinor

The GBS accordingly represented the biggest challenge yet faced by Condeep builder Norwegian Contractors (NC). It surpassed all previous platform projects in both size and complexity.

Standing 174 metres high, the completed structure contained 135 000 cubic metres of concrete and roughly 35 500 tonnes of reinforcement bars (rebars). Its base section was 169 metres long and 143 metres wide, covering an area of just over 1.8 hectares – or three football pitches.

Its 24 cells could store about 1.8 million barrels of oil, and 98 steel and concrete skirts were installed under its base..[REMOVE]

Fotnote: Steen, &., & Norwegian Contractors. (1993). På dypt vann : Norwegian Contractors 1973-1993. Oslo: [Norwegian Contractors]: 44.

By comparison, Statfjord A and all the other previous Condeeps had 19 cells and three shafts. They had a base area of 8 000 square metres, 89 000 cubic metres of concrete and 17 240 tonnes of rebars.

An important part of the GBS’s function was to transport itself and the topside out to the field. And big benefits were obtained by completing as much as possible of the support structure, topside and outfitting in sheltered inshore waters, before towing the platform out and sinking it on the field without any preparation of the seabed.

One design parameter for the GBS was the ability to support a topside tow-out weight of 35 000 tonnes. The corresponding figure for Statfjord A had been 20 000 tonnes. So the Statfjord B GBS had to be substantially increased in size to cope with the extra weight. Its buoyancy needed to be high, with a corresponding large volume of ballast where the moment between buoyancy and ballast was small.[REMOVE]Fotnote: Dahl, Per C. og Olsen, Olav.  (1978, 20. oktober). Statfjord B – interessant konstruksjon med mange nye trekk. Norsk Oljerevy Ba 4, nr. 7/8. 

As mentioned above, the base area was increased from about 8 000 square metres on the earlier Condeeps to no less than 18 000 square metres in order to ensure sufficient buoyancy. Cell storage was increased from 1.2 million tonnes on Statfjord A.

Another reason for such a big expansion in the base area was that seabed conditions at Statfjord B’s intended location were significantly poorer than for the A platform. Several innovations were developed to alleviate this problem.

Bygging av betongunderstellet,
The cellar. Photo: Leif Berge/Equinor

First, the GBS was provided with a “cellar” section, an enclosed space under the cells and above the base plate. In addition to helping overcome the bottom conditions, this solution had several advantages.

It provided space for piping systems which had been cast inside the concrete on earlier Condeeps, for instance. Since the cellar was dry until the cells had been cast, pipework could be installed during that period.

The external pipelines – risers – to and from the platform had been installed outside the cell walls on earlier Condeeps, which called for extensive diving work to weld pipes together on the seabed. But the cellar on Statfjord B provided space to conduct the risers through pipes directly to the fourth shaft, where they could be welded in the dry once this “riser” shaft had been emptied of water.[REMOVE]

Fotnote: Dahl, Per C. og Olsen, Olav.  (1978, 20. oktober). Statfjord B – interessant konstruksjon med mange nye trekk. Norsk Oljerevy Ba 4, nr. 7/8. 

Bygging av betongunderstellet
About 35 500 tonnes of reinforcement bars were used in building the GBS for Statfjord B. Photo: Mobil Exploration Norway Inc./Norwegian Petroleum Museum

Installed beneath the cellar/base plate, the 98 steel and concrete skirts also had several functions. Plans called for the platform to be installed directly on the unprepared seabed. As in many other areas, the upper layers of the sea bottom were less consolidated than those lower down.

So rigid steel skirts were important, because they would cut down into the soil to reach a depth which could bear the load. They also protected against the seabed being washed out, and served as a framework for concrete grouting beneath the platform.

Pressure in the skirts was also kept below the ambient level. Combining overpressure and underpressure in the spaces between the various skirts, the platform could be manoeuvred more surely during its installation.

Thanks to the skirts, too, the structure could also be safely placed on sloping ground. Maintaining overpressure in the relevant skirts kept the platform level until grouting had been completed.[REMOVE]

Fotnote: Dahl, Per C. og Olsen, Olav.  (1978, 20. oktober). Statfjord B – interessant konstruksjon med mange nye trekk. Norsk Oljerevy Ba 4, nr. 7/8. 

Yet another innovation on Statfjord B was the increase in the number of shafts from three to four. Experience with Statfjord A and other earlier concrete platforms showed that a four-shaft layout was more appropriate for supporting the topside. Although the Statfjord B GBS was built in the same way as its predecessors at Hinnavågen outside Stavanger, it incorporated so many changes that it ranked as a new Condeep generation.

Project organisation

Bygging av betongunderstellet
Understellet til Statfjord B ligger i byggedokken til Norwegian Contractors i Hinnavågen ved Stavanger vinteren 1979. Foto: Norsk Fly og flyfoto AS/Norsk Oljemuseum

A dedicated organisation comprising NC’s own personnel was needed to manage and control such a giant project. Both Mobil as the client and NC also hired external expertise, with Mobil awarding a consultancy contract to EMC – a joint venture between Brown & Root and Norway’s NPC.

For its part, NC hired Grøner og Noteby to support the construction management team and to conduct quality control of its own work. It also hired the Olav Olsen A/S consultancy to do construction engineering, prepare drawings and make calculations for the concrete work, the Norwegian Geological Institute (NGI) for foundations and instrumentation, and Det Norske Veritas (DNV) for technical calculations.

The Norwegian Petroleum Directorate (NPD), which was responsible for seeing that work complied with official safety regulations, hired Dr Ing Aas Jacobsen to check drawings, calculations and the execution of concrete and steel construction. This consultancy had done the same job on Statfjord A.

With DNV checking the mechanical systems, drawings were accordingly assessed by three different bodies – Aas Jacobsen for the NPD, DNV for NC and EMC for Mobil. The level of change orders for building the Statfjord B GBS was low.[REMOVE]

Fotnote: Moe, J. (1980). Kostnadsanalysen norsk kontinentalsokkel : Rapport fra styringsgruppen oppnevnt ved kongelig resolusjon av 16. mars 1979 : Rapporten avgitt til Olje- og energidepartementet 29. april 1980 : 2 : Utbyggingsprosjektene på norsk sokkel (Vol. 2). Oslo: [Olje- og energidepartementet]: 231.

Work begins

Bygging av betongunderstellet
Before the GBS was submerged, temporary entrances were provided into the concrete cells. From the Monthly report Statfjord B, NC/Mobil Exploration Norway Inc.

NC began the job of readying the construction site before Mobil had awarded it the contract to build the Statfjord B GBS. The first step was to move a pipeline used to pump out seawater which seeped under the sheet pile retaining wall. This extended too far into the dock.

A larger foundation was also required. It had previously covered some 0.8 hectares, but the planned dimensions of Statfjord B meant this had to be expanded to two hectares. After an investigation, it was decided that the existing foundation could be incorporated in the new one.[REMOVE]Fotnote: Stavanger Aftenblad. (1978, 24. januar). Klar for B-plattformen.

Once the contract had been formally signed, work on improving the ground began before the new foundation was cast. The dock had to be drained and part of the spoil had to be removed. A good base for the concrete foundation was important – it had to cope with a weight of 110 000 tonnes which was unevenly distributed.

The bottom section of the GBS was towed out of the dry dock on 11 June 1979 and moored in the Gands Fjord off Stavanger while preparations were made to slipform the cells. This tow-out was a critical phase. The section had to be pulled out of the inner dock for 100 metres, before being turned 23 degrees and then towed out of the opening.

Very little wind could be tolerated, and the job had to be postponed twice. The first attempt was aborted after it transpired that bottom conditions at the dock gate had not been properly prepared, so that the draft was too shallow. A 70 000-cubic-metre support bank had to be removed. Excessive wind prevented the second try.

But everything went according to plan the third time, and the bottom section was pulled out of the dock by winches with just 70 centimetres of clearance over the bottom.[REMOVE]Fotnote: Stavanger Aftenblad. (1979, 28. juni).

Once the structure was clear of the dock, the winch cables were severed and the tugs took over. Compressed air, buoyancy and 20 000 horsepower divided between five tugs made it possible to move Statfjord B to the mooring site at a speed of two-three knots.

Attaching and tightening the moorings took two days.[REMOVE]Fotnote: Rogalands Avis. (1979, 11. juni). Condeep-utslep med forviklinger.

The chains intended to hold the structure in place were fixed to new attachment points. Four lengths measuring a total of six-seven kilometres were used.

The chains were of better quality than those used before, since the GBS would be significantly larger. With a breaking strength of 1 500 tonnes, compared with 1 300 tonnes before, they were attached to Lihalsen and Einerneset on the eastern shore of the Gands Fjord, and Vaulen and Kvalaberg on the western side. The attachments were simpler in design than their predecessors. No winches were placed on land, only steel plates set into the bedrock.[REMOVE]Fotnote: Stavanger Aftenblad. (1979, 5. januar). Svær kjetting til Statfjord b. 

Bygging av betongunderstellet
Pushing wheelbarrows was a popular but tough job. Photo: Leif Berge/Equinor

Slipforming of the cells started at the same time as the school summer holidays. This was important in order to recruit students and thereby obtain sufficient labour. The job was well paid, and it was not difficult to get workers. People had to be turned away. Most of the holiday personnel pushed wheelbarrows, but NC also held courses for them in iron fixing and formwork construction.

This was the most hectic period, with 1 150 people at work. NC’s own personnel accounted for 860 of these. The slipforming continued around the clock for 27 days, making it the world’s biggest operation of its kind until then. A total of 58 000 cubic metres of concrete were poured from wheelbarrows. Each of the latter held 80 litres and, to achieve the desired slipforming speed of 1.5 metres per second, one wheelbarrow had to be filled every three seconds.[REMOVE]Fotnote: Steen, &., & Norwegian Contractors. (1993). På dypt vann : Norwegian Contractors 1973-1993. Oslo: [Norwegian Contractors]: 44.

The work was heavy and a high pace was maintained. Workers were divided into four shifts. After six hours of pushing wheelbarrows or binding rebars, the body ached and fingers were stiff. Concrete was mixed in a plant on a barge moored alongside the GBS.

A dozen temporary office buildings for administrators were also installed out in the fjord. Personnel were ferried to and from the GBS by high-speed craft.[REMOVE]Fotnote: VG. (1979, 12. juni). Betong-gigant PÅ FJORDTUR.

Bygging av betongunderstellet
The completed GBS in the Gands Fjord, with the concrete mixing plant visible at bottom left. From Monthly report Statfjord B. NC/Mobil Exploration Norway Inc.

Slipforming the cells was carefully planned, with no margin for error. Hundreds of hydraulic jacks controlled by laser beams thrust the formwork upwards. The job was completed by 18 July, and a temporary halt was called to permit completion of the cells and make preparations for slipforming the shafts. That operation began the following January, and the top was reached on 24 February. The GBS was now no less than 174 metres high. Despite the tight schedule, work was finished a day early.

NC now had to reduce its workforce again, from 650 people to about 350. The 150 employees recruited for slipforming the shaft moved on to other jobs, while many of the remaining 150 returned to jobs with the partners in NC – Furuholmen, Høyer-Ellefsen and Selmer. NC found work for the rest elsewhere, including at Rosenberg Verft. The latter was in the middle of building the Statfjord B topside.[REMOVE]

Fotnote: Rogalands Avis. (1980, 11. mars). På toppen av Statfjord B. 


Work on the Statfjord B GBS proceeded largely without dramatic incidents, but one accident did occur in December 1979. This involved a silo containing 50 tonnes of fine-crushed iron ore, a small barge and a loading shovel worth several hundred thousand kroner, which sank in the Gands Fjord. Nobody was injured.

The mishap occurred during discharging of fines (iron ore crushed into small-grained particles) representing half the 40 000 tonnes due to be used as ballast in the GBS base. Two cranes on the ore carrier were transferring this cargo to two silos standing on separate pontoon moored to the platform. Conveyor belts ran from the silos to the GBS.

Without informing the crane driver, the belt from one silo was halted to check some hoses. The driver thought ore was still flowing out of the silo and continued loading even when the latter was full. Thanks to the overload, the pontoon concerned developed a list, the legs supporting the silo broke and the container fell onto a barge moored alongside and carrying a loading shovel. Silo, iron fines, barge and shovel vanished in 243 metres of water and a thick layer of bottom mud.[REMOVE]

Fotnote: Stavanger Aftenblad. (1979, 21. desember). Shovel og silo gikk til bunns. 

Published May 23, 2018   •   Updated May 4, 2020
© Norsk Oljemuseum
close Close

Statfjord agreements

person By Håkon Lavik, former Statoil employee
An extensive network of agreements weaves a web around operations on the Statfjord field. They either regulate these activities or influence what can and cannot be done. In addition come contracts with other licences and fields on the sale or exchange of services and so forth.
— Statfjord C. Photo: Øyvind Hagen
© Norsk Oljemuseum

This set of agreements is fairly intricate and complex, but nevertheless makes the whole operation possible. They include:

  • the dividing line treaty
  • licences
  • unitisation deals
  • the Statfjord treaty
  • the bridging agreement
  • the production swop agreement

Dividing line treaty

The hierarchy of agreements actually starts with the treaty between the UK and Norway which defines the median line between their continental shelf areas in the North Sea. Signed in 1965, this agreement is rooted in international law pursuant to the UN Convention on the Law of the Sea adopted in 1958.

This convention provides several possible principles for dividing up a continental shelf between states. But Norway opted for the median line principle when it began negotiating on North Sea boundaries in 1963. That means the dividing line is drawn midway between the base lines – which define the coasts – of the states bordering the continental shelf area in question. This principle is applied in all the treaties entered into by Norway on North Sea boundaries in 1965. Only the treaty with the UK is significant in Statfjord’s case.

A minor curiosity which had consequences for Statfjord arose as a result of the dividing line treaty. The boundary with Denmark, Germany, the Netherlands and the UK was determined in 1965 from the Swedish-Norwegian border northwards to 61°20’40”N. Those responsible for defining the dividing line thought they had settled it for many generations to come. But a need to extend the boundary further north arose within a few years.

This was also the origin of the Norwegian practice of referring to operations on the NCS as being south or north of the 62nd parallel. When Norway put parts of the North Sea on offer to oil companies in 1965, it informally extended the boundary northwards to 62°N and then along this parallel of latitude to the Norwegian mainland. That established a northern limit to the North Sea. The only motive was the desire for a practical division of the blocks to be put on offer, since the boundaries of each full quadrant of 12 blocks is defined by one degree of both latitude and longitude.

Since Statfjord lies mainly north of the 61st parallel, this rather unclear boundary meant that the British refrained from extending licences right up to the dividing line when awarding acreage in this part of the UK continental shelf during 1971. That created problems later on.

A rather amusing story can also be told in relation to the determination of continental shelf boundaries. During the negotiations on the law of the sea convention in the late 1950s, Norway’s sole concerns were to safeguard freedom of the seas for shipping and clear fishing limits. As a result, Norway did not ratify the convention until 1963. And it was not until 1973 that the boundaries of fishing zones in the North Sea coincided with the median line. So before it could offer licences for petroleum exploration, Norway had to ratify all parts of the law of the sea convention, declare Norwegian sovereignty over the NCS and then negotiate dividing lines in accordance with the rules in the convention.

Out by 13 kilometres. When the dividing line with the UK was under negotiation in 1964, a mapping error could have cost Norway the whole Ekofisk field and thereby billions of kroner in oil revenues.The evening before the boundary treaty negotiations between the two countries were to be concluded, the representative of the Norwegian Hydrographic Service at the talks began to wonder whether there might be something wrong with the calculations used to determine the dividing line. He contacted the geodetic department at the Geographical Survey of Norway (now the Norwegian Mapping Authority) and asked it to check the matter.Because time was short, the department had to work on mathematical formulae throughout the night under the leadership of Gunnar Jelstrup to check the coordinates involved.“The results were almost frightening,” Bjørn Geirr Harsson, former principal engineer at the Norwegian Mapping Authority, told the website. “They discovered that the southernmost point lay almost 13 kilometres closer to the Norwegian coast than the British. In addition, the two sides had used the wrong map to determine the median line.”


Shell and Esso contacted the Norwegian government in the autumn of 1972 to report that the recent Brent discovery in the UK North Sea might extend onto the NCS. That presented the authorities in Norway with a problem. According to the regulations, blocks on the NCS could only be awarded through advertised licensing rounds. That meant the first step had to be an amendment to the rules.
This was done in early 1973, and it was announced in March that blocks 33/9 and 33/12 were to be awarded outside the normal licensing rounds. Applications were received at the end of April and, following negotiations, Norwegian production licence 037 was awarded on 10 August 1973. Exploration on Norway’s side of the dividing line could thereby begin.

The UK licence which covered the possible Statfjord field had been awarded in 1971. Block 211/24 (the P104 licence) covered most of the area. Because the eastern limit of the licence did not coincide with the dividing line, however, a new one had to be awarded as P293 to cover the narrow intervening corridor. This was done in early 1974. P293 moreover had the same licensees – Conoco, Gulf (later Chevron) and the British National Oil Corporation (BNOC – later BP) – as P104 to avoid any conflicts of interest. The only aspect which did not harmonise was the duration of the Norwegian and UK licences, but nobody saw the significance of that in 1973-74.


The dividing line treaty contained some vague formulations that, if a reservoir extends across the boundary, efforts will be made to reach agreement on mutual exploitation. The existence of a common reservoir or reservoirs on either side of the boundary must also be proven.

After the Statfjord discovery in the Norwegian North Sea was announced on 26 February 1974, the British had to establish through drilling that this structure extended into the UK sector. The British operator, Conoco UK, drilled a well in the summer and autumn of the same year which clearly showed that the discovery comprised several shared reservoirs.

Negotiations accordingly began on joint development and production, and lasted until the spring of 1976. Agreement was then reached by the licensees on the principles for an accord on joint utilisation. The Statfjord Unit was established in the summer of 1976, with the first management committee meeting in September 1976.

The agreement was not formally finalised and signed until 1979, but a unitised development of Statfjord began in June 1976. This meant that a separate joint venture was established to develop and produce the petroleum-bearing strata, with a common operator. The equity holdings of the licensees were allocated in accordance with their interests in the original licences, multiplied by the percentage division of the reserves between the two countries. It was estimated in 1976 that 88.88 per cent of the field lay on the NCS.

In other words, it was the sub-surface reserves which were merged and not the licences themselves. Formally speaking, the unit embraces a cube which begins 20 metres above the top of the uppermost Brent formation and terminates 20 metres beneath the base of the lowest Statfjord formation. It might seem confusing that the field and one of its formations bear the same name, but the reason is that the latter has been named after the field where it was first identified.

The 1976 pact has a simple and straightforward designation: the Unitisation and Unit Operating Agreement Statfjord Field Reservoirs in the Norwegian and United Kingdom Continental Shelf. Although dated 1 June 1979, this accord actually became effective from 1976. As the title indicates, it is also an operating agreement which regulates how the field should be developed and operated.

Each licensee has a vote in the management committee for the Statfjord Unit, which matches their calculated interest in the field. The agreement also provides that these interests will be calculated to five decimal places.

A binding decision requires the support of at least 70 per cent of the licensees, and only a few exceptions exist to this voting rule. The division of the reserves between the two countries requires 100 per cent support, for instance. So does the use of Statfjord’s facilities by other fields and the cessation of production.

The licensees also contribute to all investment and costs on the basis of their per-centage share of the field, and own a corre-sponding proportion of the oil and gas produced.

Other provisions in the unitisation agreement specify that the division of assets in the reservoirs can be reassessed at certain intervals. These “redetermination” rules (see separate article) have led to a number of bitter conflicts between the licensees and between Norway and the UK. The last process of this kind was concluded in 1998.

Should the percentage split be amended, all investments and the whole allocation of reserves back to day zero in the field’s history must be redistributed between the licensees. Since such a large proportion of the assets had been produced by 1998, any adjustment would have dramatic consequences for those licensees whose share is reduced. It was accordingly agreed that the redetermination in that year would be the last. This concluded that 85.46869 per cent of Statfjord is Norwegian.

The unitisation agreement has also been amended and updated a number of times. More than 20 change agreements to the original accord had been approved up to 2009. These alterations have been required to take account of conditions not foreseen in 1976.

According to the original agreement, the working language in the Statfjord Unit is American English. All agreements are accordingly written in that language with the exception of the Norwegian licence for PL 037. All documentation and reporting are also in English.

The unitisation agreement provides in addition for the resolution of possible conflicts between the licensees in the joint venture. In addition come provisions on where and how assistance can be sought if issues cannot be resolved. The Statfjord Unit licensees are to seek help from the international chamber of commerce in Switzerland’s Vaud canton, which embraces Lausanne. Such aid has never been required.

 The Statfjord treaty

Talks over the unitisation agreement were paralleled by negotiations on a separate treaty for Statfjord. This Statfjord Treaty of 1979 between Norway and UK was finally ratified on 16 October 1979. It was also ready in principle in 1976, but was only finalised just before production began. The treaty makes it possible to produce Statfjord as a single unit. It contains provisions on joint exploitation of the field even though it is split between two different countries.

Why is such unitised development and production important? During the earliest era of the petroleum industry in the USA, and later in Mexico, an oil and gas discovery acted as a signal for all and sundry to rush in and start drilling and producing from neighbouring properties. The result was that many fields were damaged by over-exploitation, so that only a fraction of their reserves were recovered. A unitised and planned development ensures that a much larger proportion of the assets can be produced.

The Statfjord treaty also contains provisions on how possible conflicts between the two countries should be resolved. This has permitted a coordinated and peaceful utilisation of the field. Governments in many other countries have marvelled that this has been possible, and have wanted to develop similar treaties and agreements.

According to the treaty, operations on the field will be pursued in accordance with Norwegian law and statutory regulations. This is because all the installations are on the NCS and operated from Norway, and because the operator is a Norwegian company.

Another treaty covering the nearby Murchison field was signed at the same time as the Statfjord accord. This made it possible to produce Murchison as a single unit in the same way as Statfjord. Since the Norwegian PL 037 licensees originally held 22 per cent of Murchison, it has been developed and produced from the UK side. So the Murchison treaty is a mirror image of that for Statfjord.

 Bridging agreement

The bridging agreement was entered into by the British and Norwegian licensees in the Statfjord Unit. Known as the Agreement between P104 (293) and PL037 Groups, this was ready at the end of 1990 but not signed until 1 June 1991 at the same time as the first change agreement. The reason for the delay was that it was not needed before then, and the first change agreement corrected an oversight about redelivery points for petroleum from the field. Such a point is one or more locations whether those delivering oil and gas to Statfjord for processing get their products handed back for onward transport.

A bridging agreement was required because the unitisation agreement contains provisions that petroleum which might be proven in the original Norwegian and British licences would have the right to use the production facilities on the three Statfjord platforms for processing if spare capacity was available. Substantial additional reservoirs – Statfjord East and North – had already been proven in PL 037 before unitisation in 1976. Terms were accordingly incorporated in the unitisation agreement on the way “non-unit operations” were to be pursued. But supple-mentary rules were needed in order to develop Statfjord East and North.

Work on developing these two satellites began in 1986. The position of Statfjord North was straightforward, since the whole field lies within PL 037. But it falls outside the Statfjord Unit area. That means that the Norwegian licensees in Statfjord, which had the sole rights to Statfjord North, were entitled to use the production facilities if spare capacity was available. Although this was incorporated in the unitisation agreement, the British licensees had reserve-tions and wanted certain details to be specified more precisely.

Statfjord East, on the other hand, lay only partly in PL 037. The rest extended into the adjacent PL 089 licence. The Norwegian Statfjord licensees accordingly had the right to process half of Statfjord East under the provisions of the unitisation agreement, but not the part which lay in PL 089.

The British licensees were concerned in 1986-87, with good reason as it turned out, over what was colloquially known as the prioritisation rules. According to the unitisation agreement, oil and gas produced from the Statfjord Unit reservoirs had a prior right to use the processing and export facilities. If production capacity was to be sold to others, the external volume had to accept that it took second place – in other words, rest content with the capacity available after the Statfjord Unit’s needs had been met.

So the bridging agreement set a number of conditions which mean that the Statfjord facilities can be used by others – providing this does not interfere with the Statfjord Unit’s own output. The licensees of other fields are welcome to invest in increased processing capacity and to acquire the prior right to use this, but the Statfjord Unit’s licensees must unanimously agree on how much capacity can be offered to others.

The bridging agreement also states that all oil from Statfjord East is to be regarded as produced within the PL 037 licence. That issue should therefore have been resolved, or so people thought in 1991. But a couple of complications were to emerge.

Statfjord East was unitised and a joint venture established in 1991. This field thereby became a separate legal entity within PL 037, and a separate tie-in and processing contract was needed to use the Statfjord facilities. But this was not entered into with the Statfjord Unit but with PL 037, because the latter had the right under the bridging agreement to have the whole of Statfjord East processed pursuant to the provisions in the Statfjord unitisation agreement.

However, a minor point had been forgotten. Statfjord East, including the part which lies in PL 037, contains some gas. The oil from the whole field was covered by the bridging agreement and thereby ranked as a second priority, but nobody had thought about the gas. When the time came that this had to be clarified, the gas from that part of Statfjord East which originally lay in PL 089 was assigned fourth priority for using the Statfjord facilities. That might sound a little cumbersome – the oil and gas arrive at Statfjord C in the same pipeline and are separated there, but have different rights to use the facilities. In practice, this has functioned straightforwardly.

When Statfjord East and North were approaching the start to production, it was clear that processing capacity on Statfjord C was far too small to handle output from these satellites. Statfjord East was due to be ready to produce on 1 October 1994. The day before, on 30 September, a change agreement was adopted for the bridging accord.

This second amendment has been called the underlifting agreement. The satellite units purchased the right to process up to 156 000 barrels (25 000 standard cubic metres) per day on Statfjord C, and the Norwegian licensees in the Statfjord Unit reduced their production from that platform to make room for that volume. Since the British licensees were unwilling to accept such a reduction, they received their share of the output as if the satellites were not using the capacity. In reality, they received oil from Statfjord East and, from January 1995, from Statfjord North.

In order to give the satellites first priority in this way, the British licensees also received a fee of a few US cents per barrel from the satellite licensees. In principle, the Norwegian licensees purchased processing capacity for the satellites.

That made it possible to produce the satellite fields at full capacity, without restrictions. This was also important because they had been developed with subsea wells. Constant start-up and shut-down of such facilities, with pipeline transfer of the wellstreams on the seabed, can cause hydrate (a form of hydrocarbon ice) to form in the lines and block them.

Such hydrate plugs are extremely difficult to dissolve. Anti-freeze, usually methanol, can be injected into the pipelines. But methanol has the disadvantage that reacts with the gas and undermines the quality of the gas exported. If the gas falls outside the specified quality parameters, it attracts a lower price.

This underlifting continued for a number of years, and meant in reality that the UK licensees received too much oil in relation to actual production from the Statfjord Unit. Repayment for this British overlifting was supposed to have started in late 1998 but was postponed for five years until 2003. The Norwegian licensees benefited heavily from this, because oil prices were below USD 10 per barrel in 1998 but were rising in 2003 and three-four times higher.

The underlifting agreement is an example of how an issue can be resolved which could otherwise have caused problems for the satellite licensees, who had invested in their development and had to secure a return on that capital.

The production swop agreement

One of the first acts of the Labour government which took office under Gro Harlem Brundtland in 1986 was to order a temporary 10 per cent cut in Norway’s oil output. Intended to support Opec and boost oil prices, this measure also applied to Statfjord – particularly because that field was by far the largest on the NCS at the time.

But the UK government had no desire to reduce the country’s oil production, and refused to allow the British Statfjord licensees to participate in any diminution of the field’s output. The solution was that Statfjord was exempted from the Norwegian measure, and the cut which should have occurred there was switched to Gullfaks instead.

This arrangement was put in place by Statoil, and a swop agreement was entered into. The Gullfaks licensees would get back the production they had postponed in the years after the Norwegian measures had ended. It was not until the late 1990s that this account was finally settled and the agreement terminated.

A minor oddity can be noted here. When the Norwegian government announced its production restrictions in June 1986, oil prices immediately rose by USD 0.50 per barrel. On the same day, Statoil had an oil cargo from Statfjord ready to depart. It was resolved to wait to sell this consignment until it was clear what the new Labour administration would do. The cargo was sold after the price had risen. With 770 000 barrels on board, the company earned at extra USD 335 000 by waiting. That represented about NOK 2.5 million in additional revenue on this one cargo.

Published October 30, 2019   •   Updated January 28, 2020
© Norsk Oljemuseum
close Close

Building the topside

person by Trude Meland, Norwegian Petroleum Museum
Moss Rosenberg Verft (MRV) secured Norway’s largest industrial assignment until then when it was awarded the contract for building the topside for Statfjord B and for mechanical outfitting in the shafts of its concrete gravity base structure (GBS).
— The topside of Statfjord B is assembled at Rosenberg Verft. Photo: Mobil/Norwegian Petroleum Museum
© Norsk Oljemuseum
Bygging av B-dekket
Kuletankeren, Khannur, ble bygget ved Moss-Rosenberg skipsverft i Stavanger i 1977. Foto: Ukjent/Norsk Oljemuseum

MRV had specialised in recent years in building gas carriers, but was now going to outfit a module support frame (MSF) covering no less than 7 800 square metres. Its Rosenberg Verft yard in Stavanger had to be further developed before work could begin.

The latticework MSF was to be established on four concrete pillars which corresponded exactly with the tops of the GBS shafts. Installation work started in November 1978. Space also had to be made available for storing materials, building modules and – since the labour force would necessarily expand considerably – places to eat, sleep and work. Rosenberg Verft had 1 700 permanent employees. In addition, blue-collar and white-collar workers from a number of sub-contractors, service companies and Mobil had to be found space at the yard’s Buøy site. Some 3-4 000 people were due to be working there during the Statfjord B project.[REMOVE]

Fotnote: Roalkvam, G., & Stavanger jern- og metall. (2002). Fra ambolt til plattform : Jern- og metallarbeiderne i Stavanger. Stavanger: Wigestrand: 149

Four hectares were added to the site, in part by filling in the bay off the yard and burying the Kattaskjæret rocks – where the topside was to stand – under spoil. The seabed was blasted and dredged to install a deepwater outfitting quay suitable for both offshore facilities and big ships.

Utslepet av Statfjord B understell til Gandsfjorden, bygging av b-dekket,
Everything has been readied to receive the MSF sections at Rosenberg Verft. The four concrete pillars are sized and positioned to be identical with the tops of the GBS shafts being slipformed simultaneously by NC a little further down the fjord. Photo: Øyvind Hagen/Equinor

The former mould loft was converted into a drawing office for 60-70 people. Temporary buildings were established in the quay area to provide accommodation for 300 people and canteens for 500. Rosenberg Verft also had five accommodation blocks with beds for 25-30 people in each.[REMOVE]Fotnote: Nerheim, Jøssang, Utne, Dahlberg, Jøssang, Lars Gaute, Utne, Bjørn Saxe, . . . Kværner Rosenberg. (1995). I vekst og forandring : Rosenberg verft 100 år 1896-1996. Stavanger: Kværner Rosenberg: 372.Blasting work was completed on schedule in mid-February. The four concrete pillars to support the MSF were ready to be towed out of the dock in late April and in position during May.[REMOVE]Fotnote: Nerheim, Jøssang, Utne, Dahlberg, Jøssang, Lars Gaute, Utne, Bjørn Saxe, . . . Kværner Rosenberg. (1995). I vekst og forandring : Rosenberg verft 100 år 1896-1996. Stavanger: Kværner Rosenberg: 372-375.

The MRV board also resolved in February to invest another NOK 140 million in upgrading the facilities. Just over 1.4 hectares of land was acquired to accommodate new warehousing, changing rooms and a canteen. Two warehouses were built for intermediate storage of shaft equipment, along with a temporary pipe welding shop. In addition came a new sandblasting and painting shop, further production and transport equipment, and a new office and administration building.[REMOVE]Fotnote: Nerheim, Jøssang, Utne, Dahlberg, Jøssang, Lars Gaute, Utne, Bjørn Saxe, . . . Kværner Rosenberg. (1995). I vekst og forandring : Rosenberg verft 100 år 1896-1996. Stavanger: Kværner Rosenberg: 373.

Work advances in Fredrikstad and Egersund

The latticework MSF was to be built in two identical halves at Fredrikstad Mekaniske Verksted (FMV) south-east of Oslo and Kværner Brug Egersund (KBE) south of Stavanger respectively.

Eighty people worked at the latter on a structure measuring 114 by 55 metres, with a height of 14 metres to the main deck. The total weight of this colossal frame was no less than 2 400 tonnes. Its steel plates were up to 50 millimetres thick.

The timetable was tight, and delays could have serious consequences for the rest of the project. Whether the Egersund and Fredrikstad yards would succeed in meeting their delivery deadlines was the first major source of uncertainty in the construction of the Statfjord B topside.

Both fabricators fell a little behind schedule initially because of problems with approval of welding procedures. Welders had to be certified to the American ASME standard, and needed a special course to achieve the required G-6 grade. The weld quality demanded was very high, and it took longer than expected to get the necessary procedural tests approved.

The problem was overcome, partly because in-house welders acquired the necessary certification and partly by hiring in specialists from Sweden and Finland. In addition, the yards succeeded in getting the delivery date extended by two weeks because a good deal of extra work was added for the MSF sections.

KBE operated at full throttle, even during the Easter holiday. The Directorate of Labour allowed it to work throughout the public holiday except for Easter Sunday, when the yard itself wanted a well-earned break.

It was not difficult to get people to work at Easter. Many of the personnel at the yard came from other parts of Norway or the Nordic region, with a long journey home for just a few days off. The financial advantages of working on public holidays were another motivating factor.[REMOVE]

Fotnote: Stavanger Aftenblad. (1979, 17.april . Travel påske ved Kværner.

FMV built the other section in parallel. The work progressed, but the yard had problems recruiting qualified welders. Other Norwegian yards had promised to help with skilled personnel, but few actually turned up. FMV accordingly had to hire 150 specialist welders from Sweden, and eventually eliminated the delays.[REMOVE]Fotnote: Nerheim, Jøssang, Utne, Dahlberg, Jøssang, Lars Gaute, Utne, Bjørn Saxe, . . . Kværner Rosenberg. (1995). I vekst og forandring : Rosenberg verft 100 år 1896-1996. Stavanger: Kværner Rosenberg: 376.

When the FMV union downed tools in May for a one-hour “political” strike, along with 250 white-collar staff, a number of people expressed concern about progress with the Statfjord B project. The stoppage was implemented to persuade the government to secure new work for the yard. Like the rest of Norway’s shipbuilding industry, FMV was hard-hit by the international crisis in the shipping industry.

The union branch decided at the same time that all overtime working would halt immediately and demanded that further recruitment of contract labour should cease. The Swedes and Finns already at the yard were allowed to remain.[REMOVE]Fotnote: Demokraten.  (1979, 9. mai). Vil forsinke utbyggingen på Statfjord B.

Til tross for uroen blant verkstedarbeiderne ble den justerte fristen 14. juli 1979 overholdt. 15. august var dekksrammen i Egersund ferdig, også det innen fristen.

Despite the unrest among the yard workers, the adjusted deadline of 14 July was met. KBE also completed its section of the MSF by the set date of 15 August.

Shaft outfitting

Bygging av B-dekket
Electricians check cabling / equipment on Statfjord B at Rosenberg. Photo: Rein Øverland/Norwegian Petroleum Museum

Once the expansion and upgrading of Rosenberg Verft’s Buøy site had been completed, work began on prefabricating equipment for mechanical outfitting of the GBS shafts. This included decks, stairs, ladders, platforms, foundations and ventilation channels, which could then be lifted into the shafts as the latter were slipformed.[REMOVE]Fotnote: Roalkvam, G., & Stavanger jern- og metall. (2002). Fra ambolt til plattform : Jern- og metallarbeiderne i Stavanger. Stavanger: Wigestrand: 149.

The equipment was commissioned at the yard by MRV’s own personnel, while installation in the nearby Gands Fjord was carried out by sub-contractors.

Things went a little slowly to start with. Rosenberg Verft failed to increase its prefabrication workforce to the planned level. The work fell steadily behind schedule, and the management sent a request to Mobil for an extension of the deadline. This was refused point blank. To boost progress, new steps were taken in May to recover the time lost.

Bygging av B-dekket
To get the best overview the pipe parts are scattered all over the floor. Photo: Rein Øverland/Norwegian Petroleum Museum

As early as 1978, the local union branch and the management had entered into an agreement on the use of contract labour. Nobody wanted the number of permanent employees to exceed a natural workload.[8]  In order to execute the project within the tight deadline, it proved necessary to hire in people and allocate part of the work to sub-contractors.

The union and the management agreed to give priority to reputable Norwegian companies who were able and willing to accept full employer responsibility for their own personnel while they were engaged on Rosenberg Verft’s premises.[REMOVE]Fotnote: Roalkvam, G., & Stavanger jern- og metall. (2002). Fra ambolt til plattform : Jern- og metallarbeiderne i Stavanger. Stavanger: Wigestrand: 375.

Workers were hired as far as possible from Norwegian industry, but MRV also had to take people from the rest of the Nordic region. Domestic personnel were in particularly short supply in such skilled trades as specialist welding and sheet metal work, so Swedes and Finns had to be recruited.

Bygging av B-dekket
Tight space inside the pipes. Photo: Rein Øverland/Norwegian Petroleum Museum

Under the deal with management, the local union had the right to express its views on which companies should be asked to tender for various jobs. It received help from the Norwegian Union of Iron and Metal Workers (NJMF) centrally to identify which companies were responsible and which could not be recommende.[REMOVE]Fotnote: Rogalands Avis. (1979, 21. november). Leigefirmaene skor seg.

Ali Installation A/S, for instance, was a subsidiary of Sweden’s Asken Industri AB. It had long experience of platform building in Stavanger, having leased substantial numbers of workers to Aker for outfitting the shafts of the Beryl A and Statfjord A GBSs a few years earlier. Some 70-100 specialist welders were recruited from this source.[REMOVE]Fotnote: Nerheim, Jøssang, Utne, Dahlberg, Jøssang, Lars Gaute, Utne, Bjørn Saxe, . . . Kværner Rosenberg. (1995). I vekst og forandring : Rosenberg verft 100 år 1896-1996. Stavanger: Kværner Rosenberg: 376-380.

Particularly stringent demands were set for welding pipe – and a lot of pipe was welded at Rosenberg Verft during this period. A welder had to demonstrate that they could weld in an arc or circle, and not just along a straight line.

When welding pipe, it was not always possible to get at the weld site from the inside. The seam between the pipe ends therefore had to be filled right through. And the filling had to display an exactly even pressure throughout its length, entirely free from pockets or irregularities.

Welds were carefully checked on a daily basis with such methods as X-rays and ultrasonics. No cavities were tolerated, and quality control was carried out by several bodies.[REMOVE]Fotnote: Statoil magasinet. (1980). 1.

Work was to begin in May, but this proved impossible because materials had not been supplied by the engineering management contractor (EMC), a joint venture between Brown & Root and Norwegian Petroleum Consultants (NPC).

Rosenberg Verft received both ordinary and isometric[REMOVE]Fotnote: En isometrisk tegning viser to sider av et objekt, I tillegg til topp eller bunn. Alle vertikale linjer tegnes vertikalt. Alle horisontale linjer tegnes med 30º vinkel I forhold til horisonten.drawings from EMC, but the quality of these and of the specifications was poorer than the yard had expected and too many of them had to be revised.[REMOVE]Fotnote: Aftenposten. (1979, 15. mars). Statfjord B efter tidsskjema, men skal stå fullført i tide. 

The cellar deck

Bygging av B-dekket
A prefabricated deck is lifted into place. Photo: Rein Øverland/Norwegian Petroleum Museum

Deliveries of drawings and materials had been late throughout the spring of 1979, and outfitting work for the topside was behind schedule. During the summer, however, drawings and materials for several months of work were delivered to Rosenberg Verft. With its contract personnel, the yard had secured a sufficient workforce to increase the tempo and recover some of the lost ground.
Both sections of the MSF were delivered in accordance with the revised schedule. The first structure from FMV was installed on the pillars at Kattaskjæret on 10 August, with the second from KBE following on 21 August.

These were large and heavy units which had to be positioned with a precision measured in millimetres. Local daily Stavanger Aftenblad had a reporter on the spot when the MSV section from KBE had to be moved 80 millimetres to provide the space to weld in the connection piece. He was clearly impressed by the precise character of the work.

Weighing 2 400 tonnes, the section was moved by emptying ballast tanks in the barge on which it lay so that only 55 tonnes continued to rest on the pillars. Project planner Per Gunnar Andersen at Rosenberg Verft explained how the operation was conducted: “We then jack it only 80 millimetres in, so that we have three millimetres of clearance between the girder and the connection piece.»[REMOVE]

Fotnote: Stavanger Aftenblad. (1979, 4. september). Varmt som i badstu og tre millimeter klaring.

Three millimetres was not much on a structure which extended 20 metres above the sea surface, but was crucial for welding the two sections together with the six connection pieces.

Bygging av B-dekket
The deck frame for Statfjord B consisted of hollow steel beams. Here they have placed the frame on top of the fixed concrete columns outside Rosenberg. Photo: Rein Øverland/Norwegian Petroleum Museum

This was tough and hot work. Specialist welding was carried out inside the hollow steel girders which made up the MSF. Space was limited and ventilation minimal. The internal temperature was 70-80°C because the steel had to be heated to 125°C before welding could begin. Such preheating was necessary if the steel plates – up to two inches thick – were to harden properly. It was accomplished by placing heat mats on the weld area.

However, the heat propagated through the steel, and a welder could only remain inside a girder for 15 minutes at a time before they needed to breath fresh air and let somebody else take over. Each welding team comprised three people who constantly changed places.[REMOVE]Fotnote: Stavanger Aftenblad. (1979, 4. september). Varmt som i badstu og tre millimeter klaring.

Once the two sections had been joined, they comprised that part of the topside structure known as the cellar deck. This was divided into a total of 15 areas with space for masses of equipment and structures. Fourteen of these areas were built and outfitted by Rosenberg Verft. Because they lacked walls and roofs, these were called “pancakes” – by contrast with the Lego-like modules to be placed on top of the MSF.

Lifting into cells and shafts

Bygging av B-dekket
Equipment and floor decks are hoisted into Statfjord B.'s concrete columns. Photo: Rein Øverland/Norwegian Petroleum Museum

The Uglen crane ship owned by the Grimstad-based Uglen group began lifting the first load of equipment into the GBS cells in mid-August 1979, only a week behind schedule. This vessel carried a crane 110 metres high with a lifting capacity of 450 tonnes.

Work went according to plan, and collaboration between GBS builder Norwegian Contractors (NC) and MRV functioned well. The high crane on Uglen was demounted in October for a break until the work of lifting decks and equipment into the shafts began.

The ship returned in March, when slipforming of the shafts had reached the full height of 171.3 metres – 58 of them beneath the surface of the sea. This work was completed one day ahead of schedule.

Rosenberg Verft had been given six weeks to lift in the equipment, which was all due to be installed by mid-October 1980. Prefabricated decks and other hardware were carried by the crane ship from the yard to the fjord where the GBS lay, and lifted directly into the shafts.[REMOVE]

Fotnote: Nerheim, Jøssang, Utne, Dahlberg, Jøssang, Lars Gaute, Utne, Bjørn Saxe, . . . Kværner Rosenberg. (1995). I vekst og forandring : Rosenberg verft 100 år 1896-1996. Stavanger: Kværner Rosenberg: 378.

Each component was attached to the hooks on Uglen at the yard and hung from the crane throughout the five-kilometre trip to the mooring site of the concrete structure.

Bygging av B-dekket
The decks for the cells could be installed complete with their equipment. In the shafts, the concave walls meant that the decks had to be produced in two halves and lowered vertically before being joined up. Photo: Rein Øverland/Norwegian Petroleum Museum

This work began on 16 March 1980. The individual decks were first hoisted into the utility shaft before the work of connecting them to the concrete walls started. Great accuracy was required and depended on stable weather conditions. The crane driver had to manoeuvre very precisely, since a single deck could weigh up to 400 tonnes and its clearance from the concrete wall was no more than 40 millimetres.

A good deal of the equipment due to be installed was large and difficult to put in place. The tanks for ballast water, for instance, were 11.5 metres long and six metres in diameter. Once lifted 115 metres, they allowed little room for error when being lowered into the shaft.[REMOVE]Fotnote: Status (1980). nr 5-6. Nytt fra Statfjord.

Lifting into the topside

Plans called for the MSF to be ready for module loading by 8 December 1979. In fact, the lifting operation began before that date, and a number of the prefabricated “pancakes” were put in place during December. Mobil was very pleased with the progress. A full storey of modules was installed on the MSF, and topped in its turn by a new set of 21 modules. Each of the three stories was 14 metres high.

The lifting operation was conducted over four periods. Installation in the actual MSF took place during December 1979. Seventeen modules, equipment packages and not least the quarters followed in May 1980. Dutch crane ship Balder lifted a total of 10 000 tonnes in this round, with the heaviest single lift – 1 200 tonnes – needing to be installed on the topside with 35 millimetres of clearance on each side.

Modules came from both Norwegian and foreign fabricators. These structures were packages of equipment as well as three complete quarters modules, each eight stories high.

Balder was positioned between Rosenberg Verft and the maritime college on the other side of the fjord, and moored with cables attached to six points on land at Karlhammeren, Ulsnes, Rosenberg and Tjuvholmen. The sound is 200 metres wide at this point, so there was not much room for other shipping.

Since it had a displacement of 20-25 metres and the water depth at Rosenberg Verft’s quay was only 12 metres, Balder lay in the middle of the sound and blocked the shipping channel into the port of Stavanger. Lifting operations had to be suspended for a few hours every day and the mooring lines slackened for ships to pass. Small craft could take a small diversion through the islands to reach harbour.[REMOVE]Fotnote: Stavanger Aftenblad.  (1980, 6. mai). Kjempeløft tross tåken.

Balder’s sister ship, Hermod, was ready on 23 June 1980 to perform the final topside lifts on the. Because of delays at the Franco-Norwegian joint venture UIE/Sterkoder in Kristiansund, Hermod was nevertheless forced to return in November to lift on the drilling modules. Everything was then in place except the 120-metre-long flare boom. This distinctive component was not installed until the topside had been mated with the GBS at Vats.

Modules from Stord

Bygging av B-dekket
The last part of the living quarter of Statfjord B is hoisted into place. Photo: Unknown/Norwegian Petroleum Museum

After losing the topside contract, Stord Verft had secured responsibility for nine prefabricated pancakes. But the biggest job at Stord went to Leirvik Sveis in the form of the quarters modules. This company was responsible for the whole project from design to procurement and fabrication.

Leirvik Sveis had also built the quarters module for Statfjord A, but then as a sub-contractor to Stord Verft. It now entered into a direct contract with Mobil after lengthy negotiations, as chief executive Harald Karlsson recalled:

“I think we actually negotiated with them for six-eight weeks. We were inexperienced in such talks. They were all conducted in English, which we weren’t used to. We hardly understood everything we negotiated on – and in any event not the insurance terms.»[REMOVE]Fotnote: Myklebust, A., & Leirvik sveis. (1996). Leirvik sveis 50 : Jubileumsbok for Leirvik sveis. Stord: [Leirvik sveis]: 116.

Leirvik Sveis – known colloquially as “Sveisen” (the Welding Shop) – had 50-70 employees. The company decided that it would stick with the job it was best qualified to do, namely the steel work, and use sub-contractors for everything else. It did not create its own organisation for the disciplines contracted out, but allowed the sub-contractors to establish their offices close to the fabrication site.

Engineering services were purchased from Norconsult in Oslo, where 30-35 people worked exclusively on Statfjord B. The quarters modules also included the helideck, which was fabricated at Stord Verft, and a helicopter hangar. The latter had not been part of the Statfjord A job.

The modules were constructed in the space of a year and employed 300 people at peak. With the aid of sub-contractors and about 50 contract administrators, the work was done on schedule.[REMOVE]Fotnote: Bergens Tidende. (1980, 19. april).

Exemptions from the Working Environment Act

Bygging av B-dekket
“Temporary employment agency Ali can remain”. Headline Klassekampen 24. januar 1980.

Several of the module-builders failed to complete their work on time. Rosenberg Verft accordingly had to take over part of the work so that the pancakes and modules could be installed on the topside. A total of 1 900 people were at work on the structure by 30 April 1980, including 800 personnel acquired via sub-contractors and temporary personnel agencies.

During the summer, the yard was still short of specialist pipe welders. But the lack of electricians and instrumentation installers was also beginning to be parlous. Neither EGA or Incom, responsible for electrical and instrumentation installations respectively, were able to secure enough skilled personnel in time. The Statfjord B topside began once again to slip behind schedule.

To secure the necessary workers, Rosenberg Verft launched a major advertising campaign and contacted labour exchanges directly throughout the country. It was looking for pipefitters, specialised welders, sheet metal workers, heat treatment operators, crane drivers, transport workers, electricians and cleaners. But the response was poor.

The yard was accordingly forced to turn to expensive agencies. While the topside contract had allowed for using external personnel, the need was greater than expected. Hiring in personnel was more expensive than recruiting employees. The yard had to make extra payments under collective wage agreements for living away from home, as well as meeting the cost of accommodation, food, travel home and agency management.[REMOVE]

Fotnote: Stavanger Aftenblad. (1980, 19. januar). Kostbare leiefolk.

To use contract personnel, Rosenberg Verft had to secure an exemption from Norway’s Working Environment Act. This was granted for the first three months by the County Employment Office without difficulties. Beyond that point, an application had to be made to the Directorate of Labour, which took a very serious view of a long-term arrangement.

Bygging av B-dekket
“LO declares war on contract workers.” Headline Bergens Tidende 28. januar 1980.

The Norwegian Confederation of Trade Unions (LO) was also sceptical about temporary personnel agencies and extensive use of contract labour. Such workers wanted different working time arrangements than permanent employees, drove up wages and increased inflationary pressures.

According to the Working Environment Act, it was forbidden for employees in one company to do work for another firm which already had personnel able to do jobs of the same kind or who pursued a business where such work formed a natural part of the activity.

The LO could not accept breaches of Norwegian law in order to execute major development projects, and blamed the government and the developers for setting construction deadlines which were too short. According to the confederation, financial considerations were being prioritised ahead of socio-economic aspects and it would fight this.

Most of the contract personnel wanted to work three weeks in a row, including weekends, and have the following week off. The normal working time was four weeks work with Sundays off and the following week free. Working on Sundays contravened the Working Environment Act, but Rosenberg Verft nevertheless applied for an exemption.

Its calculations for the topside contract had included the opportunity to work on Sundays and to hire agencies workers as and when necessary.[REMOVE]Fotnote: Bergens Tidende. (1980, 10. mai). Gjestearbeidere – oljealderens rallar.

Both the union branch at the yard and the Federation of Norwegian Industries (MVL) recommended that the application should be granted. Changing to three weeks continuous work would benefit not only all long-distance commuters but also the progress of the project.

The yard had an exemption until May 1980. Contract personnel lived for three weeks in the work camp and then had nine days at home. This meant they could have as normal a family life as possible. But using contract workers and exemptions from legal working time were the subject of intense discussion in the media during the spring of 1980, and the personnel involve found themselves squeezed between the Norwegian Working Environment Act and a desire to live as normally as possible.

With only three weeks in the work camp, the need for consolation drinking and drunkenness in the quarters would be reduced. It was maintained that making camp residents work four weeks at a stretch with Sundays off would guarantee drunkenness and fighting on the third weekend.[REMOVE]Fotnote: Bergens Tidende. (1980, 10. mai). Gjestearbeidere – oljealderens rallar.

An important consideration for the LO was that such an arrangement would not only apply to the long-distance commuters but also involve a number of the permanent employees. Its national organisation demanded respect for the law, and the issue went all the way to the Ministry of Local Government and Labour. Both Mobil and particularly Statoil put heavy pressure on the government to secure exemptions.

In addition to the working time issue, MRV had to secure permission for further recruitment of contract workers. This issue rumbled on in the media for a long time. Finally, the company reached a compromise settlement with the ministry and the LO which exempted the yard from the provisions of the Working Environment Act from 1 July 1980 to 1 April 1981. While it was admittedly refused permission for Sunday working, Rosenberg Verft was allowed to operate a three-week tour where employees had to be back at work after just seven and a half hours instead of the legal minimum of 10 hours.[REMOVE]Fotnote: Norges Handels og Sjøfartstidende. (1980, 2. juli). Statfjord B.

The contract workers earned a good reputation. They worked hard and were skilled at their job. While their hourly pay could be up to 20 per cent higher than for their Norwegian opposite numbers, they were heavily taxed – particularly on their living allowances – and faced a more uncertain future. They could risk being jobless at two week’s notice. But the alternatives were not bright, particularly for the Finns. Their options were either unemployment or substantially lower pay as a skilled worker at a Finnish shipyard.

Work and working time

Welders and sheet metal workers were not the only trades required to complete the topside for Statfjord B. Much of the work on the MSF required scaffolding, both fixed and suspended. Erecting this was a demanding job for specialists.

Much of the scaffolding was on the outside of the structures, and working on it could be both chilly and wet. Work had to be suspended if the wind and rain became too much. As soon as screens were in place, however, the weather was no handicap.[REMOVE]Fotnote: Stavanger Aftenblad. (1979, 4. september). Varmt som i badstu og tre millimeter klaring. 

A difficult neighbour

Work on Statfjord B was claimed to have destroyed life for local residents around the yard. While most people in Stavanger celebrated the huge contract and the construction project at Rosenberg Verft, not everyone was equally happy.

Residents on Buøy (part of an island connected to the city centre by bridges) found themselves with a massive building site at the bottom of their gardens. Large lorries thundering past, racket from the yard, the noise of hammers beating on steel and ever expanding work camps with everything these entailed set their stamp on the Bangarvågen area where Rosenberg Verft was located.

“A whole city district raped on Buøy” read one headline in local daily Rogalands Avis during June 1979. The residents felt powerless, and that nobody cared about them. Parents of small children were abused when they tried to curb the traffic. “Look after your kids, keep them in the garden,” was the response from the lorry drivers. “We’re driving on piece rates and short of time”.[REMOVE]Fotnote: Rogalands Avis. (1979, 13. juni). Bydelen som ble voldtatt.

The issue flared up again in September 1980. Under the headline “Come and live with us, Rettedal” – an invitation to the mayor of Stavanger ¬– Rogalands Avis again wrote about the degradation of the residential environment in Bangarvågen

According to residents, the area stank of sewage, it was noisy around the clock and traffic in residential streets was at motorway level. Nobody respected the 30 kilometre-per-hour speed limit. Traffic flowed from 06.00 in the morning to 01.00 the following night. When the shifts changed at 23.30, four buses drove in and out of the residential area.

Noises from the yard never ceased, with banging and crashing around the clock. The worst offender was perhaps the sandblasting shop, which was close to the houses.

In addition came the sewage stench, which derived from a pumping plant in the work camp. Large volumes of sewage from the yard were pumped into the existing drains, and the pressure created a dreadful stink. Residents felt deceived by the city council, which had promised to deal with the problem.

They complained that nobody had initially mentioned any private motoring in and out of the yard, only necessary goods and service traffic. In addition, a new flotel arrived without warning at Bangarvågen in September 1980. Safe Bristolia was a barge outfitted with quarters modules which could accommodate 500 people. When it moored, the residential area was completely surrounded by the Statfjord B facilities.

Residents were at their wit’s end, and invited mayor Arne Rettedal to come and live with them for a week to see for himself how the neighbourhood was being destroyed.[REMOVE]Fotnote: Rogalands Avis. (1980, 23. september). 

On the same day this the article appeared in Rogalands Avis, Rosenberg Verft itself asked the city council to look at the issue.

The yard wanted the politicians to decide on speed limits in the surrounding streets, define traffic routes to reduce the constant minor accidents and collisions, and install pavements. In response, the council promised that its executive committee would consider this request at its very next meeting. It also wanted to study plans for MRV and the council to buy out the local residents and convert the whole area into an industrial zone.[REMOVE]Fotnote: Rogalands Avis.. (1980, 9. oktober).

The eventual solution was that Rosenberg Verft should buy up the properties in the Bangarvågen and Tømmerodden housing estates, which bordered the yard. Stavanger council would provide replacement housing sites. Although this was not finally decided at the time, it looked likely that MRV would also build the Statfjord C topside.[REMOVE]Fotnote: Rogalands Avis. (1980, 22. november). 

Bomb threat

Few accidents occurred while constructing the Statfjord B topside, but a bomb threat was received in April 1980. “I have a message,” an anonymous caller told the switchboard at Rosenberg Verft. “Things will happen on Statfjord B tonight. I hope there won’t be many people on the platform.”

The police fine-combed the whole topside without finding either bombs or anything else which might be related to the threat. Work was not interrupted, but the meal break for the evening shift was extended by an hour while the police searched the yard. Nobody was evacuated.

It proved impossible to establish who was responsible for the threat, and no more were received. The case was shelved.[REMOVE]Fotnote: Stavanger Politikammers arkiv. Justissaker. Sak 2373/80.  

The final lap

Bygging av B-dekket
This picture is from a shift change, where it often became crowded in the stairs between the floors. Photo: Rein Øverland / Norwegian Petroleum Museum

Dutch crane ship Balder returned to Stavanger in November in order to lift the last modules from their transport barges and onto the topside. The sailing channel into Stavanger was again closed, as with the two previous lifting operations. This job was pursued without incident, and the channel could be reopened just two days later.

Progress with the project was good towards the end of 1980, although parts of the installation work lagged a little behind. More personnel were brought in, with 2 555 people employed on the topside in January 1981 – 800 more than planned.

But the Christmas holidays disrupted efforts to speed up the job. Part of the instrumentation, electrical, insulation, painting and equipment testing work was not completed in time, and had to continue at Vats and out on the field.

In mid-March 1981, the barges which were to carry the topside to Vats for mating with the GBS were in place. The structure was lifted off the pillars on 20 March.

Time for celebration

Rosenberg Verft held open house on 1 March 1981. Special invitations were extended to the families of employees to visit the site and get to know the workplace. Most of them were inside the yard gates for the first time.

They were given a guided tour of the topside and allowed to eat as many buns and Danish pastries as they could manage. Lemonade, ice cream and coffee could be consumed while Buøy School‘s marching band paraded around and played.

Once the construction of the Statfjord B topside had been completed, MRV also invited its employees and a number of other guests to a big party in Stavanger’s Siddishallen ice rink. Three thousand people assembled for entertainment, food and drink. Praise and flowers were shared out, along with NOK 300 000 to Stavanger’s Central Hospital.

The mood was further enhanced when MRV announced that it had resolved to construct a new welfare building for its Stavanger workforce at a cost of NOK 5 million. This would stand outside the actual fabrication yard, and provide facilities for physical training and meetings. It was completed in 1983.

Published May 23, 2018   •   Updated May 4, 2020
© Norsk Oljemuseum
close Close

Tie-in deals

person By Håkon Lavik, former Statoil employee
A number of agreements exist for the tie-in of other fields to Statfjord. No such contract applies to Statfjord North, however, since clause 22 in the unitisation agreement includes those fields which lie entirely within the original licence.
— Statfjord area with tie-in fields. Illustration: Equinor
© Norsk Oljemuseum

Statfjord East

Statfjord Øst i produksjon, forsidebilde, illustrasjon, Tilknytningsavtaler
Statfjord Øst connected to Statfjord C. Illustration: Equinor

The Statfjord East satellite has a separate tie-in agreement, which was entered into in June 1991. This field has been unitised and accordingly forms a separate legal entity.  The Agreement for Processing of Statfjord East Petroleum and Operation of the Statfjord East Facilities became operative on 1 October 1994, and regulates operation of this field.  A contract to which the Statfjord Unit is not actually a party, but which is significant in this context, is the unitisation agreement for Statfjord East, which makes it possible to produce the field as a single unit.


An agreement was reached in similar fashion with the Sygna Unit. This field is also unitised, with 55 per cent lying in production licence 037 and the rest in PL 089.

Produksjonsstart Sygna, forsidebilde, historie, Statfjord subsea, Tilknytningsavtaler
Sygna field plan. Illustration: Equinor

In addition to the Sygna unitisation accord, to which the Statfjord Unit is not a party, an Agreement for Tie-in and Processing of Sygna Wellstream at the Statfjord Facilities and Operations of the Sygna Facilities, also had to be entered into. Dated 16 December 1998, this makes it possible to produce, process and ship out Sygna reserves via Statfjord.

A complication arose with this field. The bridging agreement does not mention Sygna, quite simply because it did not “exist” in 1991. When work began on the field in 1997-98, the Norwegian licensees wanted to use the provisions in the unitisation agreement on the right to utilise the Statfjord facilities, as with Statfjord East and North. Since only 55 per cent of Sygna lies in PL 037, the British partners initially opposed this. A bitter conflict arose before it became clear that Sygna could be tied back to and produced from Statfjord C.

The solution was that PL 037 would pay a fee of a few US cents per barrel to the Statfjord Unit. Since the UK licensees held 14.53 per cent of the unitised field, they received this percentage of the fee. Sygna could thereby also be tied back to and operated from Statfjord.

Entitled Agreement relating to the Unitisation and Operation of the Sygna Field in Blocks 33/9 and 34/7 and   dated 16 December 1998, the unitisation settlement for Sygna creates the legal entity which operates that field. It does not involve Statfjord, which is only a party to the tie-in contract mentioned above.


Snorre tie-in, Tilknytningsavtaler
Illustration of the tension leg platform for the Snorre field. Illustration: Equinor

Another and rather different settlement preceded the satellite field contracts: the Agreement of Processing, Storage and Onwards Transportation of Snorre Crude Oil and Gas at the Statfjord Facilities. Dated 20 November 1987, this covers “second stage” separation of the oil after the wellstream has been dewatered on the Snorre A platform. The latter began production on 2 August 1992, with its output processed on Statfjord A. The tie-in agreement currently runs until 21 December 2012 (Note! The article is several years old).

In order to tie Snorre back to Statfjord, an Agreement for Tie-in Operation of Snorre Pipelines and Installation of Incremental Equipment at the Statfjord Receiving Platform had to be entered into on 20 November 1987. This specified what was to be installed and which modifications were to be made on Snorre A. The agreement related only to the construction period and is without practical significance today.

When Snorre B came to be installed, however, an additional Agreement for Tie-in of the Snorre B Pipeline and Installation of Incremental Equipment at the Statfjord B Platform was signed on 9 June 1998.

Well from Statfjord C to Statfjord East

In order to improve recovery from Statfjord East by drilling an additional well tied into Statfjord C, an Agreement for drilling of Statfjord East C-33 well and the tie-in of the well to the Statfjord C platform was entered into on 5 August 2004.


The Barnacle Accumulation Royalty Agreement is dated 10 June 2004. It relates to a small UK field located between Brent and Statfjord, where a small section lies within the Statfjord Unit area. The latter accordingly owns part of Barnacle and receives a proportionate share of revenues from its production.


A subsea template is lowered to the Vigdis field. Photo: André Osmundsen/Equinor

The Vigdis field in PL 089 receives certain services from Statfjord. Signed on 4 February 2004, the first accord here was the Agreement for Processing of Vigdis Extension Gas at the Statfjord Facilities , which makes it possible for Vigdis gas to be exported via Snorre A and Statfjord C.

To increase and maintain production from Vigdis, this field receives injection water from Statfjord under the Agreement for the Tie-in of the Vigdis Water Injection Pipeline to Statfjord C and the Provision of Water Injection Services Between the Statfjord Group and the PL 089 Group of 11 October 2007.

An additional agreement was also entered into between Statfjord, Vigdis and Statfjord East for the Statfjord late life project, since this also affects the two other fields. In force from 31 December 2005, the Heads of Agreement between the Statfjord Group and the Statfjord East Group related to the implementation of the Statfjord Late Life Project commits the field units to update their agreements to reflect the effects of the late life project.

Gas from Tordis

The Tiora separation plant is hoisted aboard the Seipem 7000 for transportation to the Tordis field. Photo: Marit Hommedal/Equinor

Tordis is another field in PL 089, which has its output processed on Gullfaks A. For Tordis gas to be exported, the Agreement on Transit of Tordis Gas at the Statfjord Facilities was entered into on 6 September 1993. This agreement was terminated after Gullfaks acquired a new gas export solution.

Gas storage

So that Statfjord North and East could produce as straightforwardly as possible and to cover the possibility that they were unable to export associated gas every day, a gas storage/modulation agreement was entered into. Modulation means that they have their gas delivered when they request it.

The Agreement for Storage of Gas between the Statfjord East and the Statfjord Group based on the Telex Offer of July 1991, which Includes Modulation, draft 17 August 1993 was signed on 1 October 1994. An exactly similar contract with Statfjord North was entered into on the same day.

These agreements have had little practical significance, since the gas was sold under the Troll commercial model, but they provided a production guarantee and opportunities for oil output in the 1994-95 start-up phase.

Published October 31, 2019   •   Updated February 12, 2020
© Norsk Oljemuseum
close Close

A giant mated

person by Trude Meland, Norwegian Petroleum Museum
The last mooring was cut. That signalled the start to the tow of the concrete gravity base structure (GBS) for Statfjord B to Vats at 07.07 on 24 February 1981, one hour ahead of schedule.
— The deck of Statfjord B lies on large barges. The concrete section is lowered in the fjord under the barges before it is raised again by ballast control and lifts the deck of 39,000 tonnes on a carefully controlled journey upwards. Photo: Norsk Fly og Flyfoto A/S/Norwegian Petroleum Museum
© Norsk Oljemuseum

Divers had descended to a depth of 55 metres to burn off four solid chains linking the GBS with the attachment points on land which had held the structure in place since it was floated out to the fjord from the Hinnavågen dry dock in June 1979. Without the chains, only four cables held the giant in place.[REMOVE]Fotnote: Statoil. (1981). nr 2.The tow could begin once these were cut.

b-plattformen, bygging,
Statfjord B's concrete gravity base structure (GBS) has started its journey from Stavanger to Yrkjefjorden in Vats, where it will be connected to the top deck. Photo: Unknown/Norwegian Petroleum Museum

Nine powerful tugs from three different companies – United Towing in the UK, Germany’s Wijsöller and Dutch Heerema – took a day and a half to move 634 000 tonnes of concrete and ballast north from the Gands Fjord off Stavanger to the Yrkje Fjord in Vindafjord local authority.

Ranked as the heaviest in the world up to that time, the tow maintained an average speed of 1.5 knots. Three tugs pulled from the front, two pushed from behind, two lay alongside the GBS to act as side thrusters, and the last two lay aft of the tow and functioned as brakes when necessary.[REMOVE]Fotnote: Rogalands Avis. (1981, 14. februar).

A total of 100 000 horsepower was deployed.

The voyage headed along the shipping route through the islands north of Stavanger. North of Finnøy, it turned eastwards and rounded Ombo to the south and east before crossing the Nedstrand Fjord and entering the Sandeid Fjord. The route then curved west again into the narrow Yrkje Fjord.

With a deep draught of 62 metres, the tow demanded a minimum water depth of 70 metres. This was no problem along the shipping channel. But the passage between the Brattholmen and Teistholmene islands at the mouth of the Gands Fjord was only 280 metres wide, and the tow’s width was 135 metres ¬– giving a clearance on either side of just 70 metres.

Great caution was needed there. Taking a tow through a narrow channel calls for short towing lines. Propeller backwash will then be so strong when it encounters the GBS that the structure becomes impossible to steer.

Norwegian Contractors (NC) had experienced this itself on the first attempt to tow the Statfjord A GBS. The solution was to use two powerful tugs to push the structure through the channel.

The route was chosen on the basis of detailed investigations. For two years, currents had been measured, meteorological statistics studied and tests conducted in the ship model tank in Trondheim.

Surveyor Bloms Oppmåling had installed a number of theodolites along the route to take sightings from land as a safety precaution. Combined with acoustic electronics on the GBS, it was used to ensure that the tow stuck exactly to the planned route, that nothing surprising occurred, and that the precise position was known at all times. Two systems with independent power supplies ensured that one would remain operational if the other went wrong.[REMOVE]Fotnote: Stavanger Aftenblad. (1981, 20. februar).

The tow was implemented without problems, and the GBS was moored on arrival in the Yrkje Fjord while awaiting the arrival of the topside it was to be mated with.

One of the world’s heaviest lifts

En gigant settes sammen,
Ståldekket til Statfjord B er bygget ferdig ved Moss Rosenberg Verft på Buøy i Stavanger, og er nå tatt over på tre lektere som skal bringe det videre til Yrkjefjorden i Vats, hvor det skal koples sammen med betongunderstellet. Foto: Leif Berge/Equinor

A month later, the topside left Moss Rosenberg Verft’s Rosenberg Verft yard in Stavanger on its way to the Yrkje Fjord. Four large barges had been manoeuvred into place at the yard with the capacity required to lift the structure from the four concrete pillars on which it was built.

Two of the barges were placed outside these supports, while the other two – Goliat 8 and 9 – were placed one atop the other and guided under the centre of the topside. Pumping ballast water out of the barges raised them until they had lifted the topside a couple of centimetres. That was sufficient to free it from the columns in preparation for the tow through the fjords to the mating site in the Yrkje Fjord.

It was not possible to pull the deck free with the tugs, so steel cables were attached to the pillars. As these were winched in, the barges carrying the topside were pulled cautiously forward.

Together with Swedish towing specialist Neptun, NC was responsible for the lift-off at Rosenberg Verft and the tow to Vats. This ranked as the first time a complete factory with an eight-storey living quarters was towed as a single package. The voyage began in the afternoon of 24 March.

The draught of the tow was only 12 metres, so the water depth in the fjords presented no problems for the topside either. Between Spolen and Klovningene just outside Stavanger, however, the passage was only about 300 metres wide, which offered very little leeway.

After maintaining an average speed of three knots, the topside reached the Yrkje Fjord safely in the early morning of Wednesday 25 March. A troublesome east wind meant it had to wait on weather at the mouth of the fjord.

Mating GBS and topside called for almost complete calm, but a weather window opened between two anti-cyclones on the Friday morning, and the operation could begin.

One plus one equals big

En gigant settes sammen,
Mating of the topside and GBS. Photo: Leif Berge/Equinor

After the tugs had manoeuvred the topside over the GBS shafts, cables and winches attached to the latter took over. They repeated the process carried out at Rosenberg Verft, but in reverse. Fine adjustments were made with the aid of jacks, which pushed the topside horizontally.

Virtually no tolerance was permitted when mating the topside and GBS. The circular shafts had to engage with four steel rings beneath the topside within an allowable variation of a few millimetres. It took 100 people on the barges and tugs to bring the deck in line with the steel rings and with the 104 bolts, each as thick as a man’s arm, which were to tie them to the concrete structure.

The GBS was moored throughout the operation, but floating in the water. According to Bjørn Vidar Lerøen, then a journalist with Bergens Tidende, the concrete structure lay like a set of submerged lemonade bottle with only the lips for attaching the crown cap showing.[REMOVE]

Fotnote: Bergens Tidende. (1981, 26. mars).

Only 6.5 metres of the 177-metre-high unit was visible above the water.

En gigant settes sammen,
Mating of the topside and GBS. Photo: Leif Berge/Equinor

Once the topside had been correctly positioned, water was pumped out of the GBS ballast tanks so that it slowly rose and eventually lifted the whole topside off the barges and onto the shafts.

The whole operation was an application of Archimedes’ Principle – if the weight of a submerged vessel is reduced, it will rise in the water. In this case, the submerged vessel was a concrete giant with a displacement of 550 000 tonnes. That meant a lot of water had to be removed from the concrete cells, and it took three days before the topside had reached its planned height of 50 metres above the sea surface.

This represented one of the most impressive marine operations the world had so far seen. To achieve the smoothest possible transfer of weight from the barges to the GBS, the former were also ballasted down with water and slowly sank lower in the sea as the concrete structure rose.

The topside was positioned with an accuracy of five millimetres. Its full weight had been transferred by Sunday 29 March and the barges could be pulled away. Eight people staffed the control room in the GBS’s utility shaft and controlled the ballast pumps in the structure, 160 metres below sea level.

Almost offshore

Once the deck had been mated with the GBS, work could begin on hooking up cables, piping and all the other systems tying together the two components.

The work of commissioning the platform had been well planned. Phase one, the initial hook-up, was handled by 150 people NC had ready in Vats. After that, Rosenberg Verft and Mobil took over the work site and some 1 000 new workers arrived to hook up countless more modules and components – both between the GBS shafts and the topside, and between various parts of the latter.

A new, comfortable work camp with beds for 462 people had been installed on the slopes above the quay area at Raudnes. A number of barges supporting temporary accommodation had also been towed into the fjord and moored.

In addition, a couple of hundred workers could be accommodated in the living quarters on the actual platform. Temporary offices, canteen and sauna had been established.

NC had built a new quay, and a daily ferry service to and from Stavanger was in operation. The boat from Rosenberg Verft left every morning at 08.00 to transport workers and visitors to the construction site. This trip took 90 minutes.

High and low voltage power lines had been laid to the construction site, and a new sewage system was installed with a treatment plant. A subscriber trunk dialling phone service was provided, although Vindafjord was the only local authority in Rogaland without STD at that time. NC had also helped to finance a new road from Åmosen to Raudnes.[REMOVE]Fotnote: Stavanger Aftenblad. (1981, 21.februar).

The labour force observed an offshore tour system, and lived at Vats while at work. They were looked after well ¬– the food from Bergenske Catering became known for its “offshore” standard.

A dedicated welfare secretary ensured that leisure activities were many and varied. These included outings to see the flowers in the Hardanger Fjord, boat hire for angling and film shows twice a week. Outings to nearby Haugesund were organised at the weekend – either to and from on the same day, or with an overnight stay from Saturday to Sunday. Various sporting activities were pursued, the library was well stocked and distance learning courses could be taken.[REMOVE]Fotnote: Rogalands Avis. (1981, 18. mars).

Among those who won contracts for the commissioning of Statfjord B was Alvide Berge from Sinnes in Sirdal, popularly known as Shipowner Tina. She had six boats at Vats, used to ferry personnel to and from the platform out in the fjord. In addition, her Oanes car ferry served as headquarters for the operations management.

Berge had started her little company as early as the construction of the Statfjord A GBS in the Gands Fjord, providing boats which shuttled between Hinnavågen and the concrete structure with everything from plastic buckets to passengers.[REMOVE]Fotnote: Stavanger Aftenblad. (1981, 28. mars).

The work in the Yrkje Fjord took four months, and one of the last structures to be installed was the flare stack. This 155-metre-long unit was lifted into place in a single operation by the world’s largest crane ship, Hermod, which arrived in June.

b-plattformen, forsidebilde, Jeg døper deg Statfjord B,
The naming ceremony of Statfjord B was held after the interconnection in the Yrkjefjord, June 17, 1981. Godmother was Mrs. Agnes Rettedal. Minister of Petroleum and Energy Arvid Johanson and other guests of honor were present. Photo: Mobil/Norwegian Petroleum Museum

On 17 June 1981, Statfjord B was named by lady sponsor Agnes Rettedal. She was the wife of Arne Rettedal, mayor of Stavanger at the time. Thirteen days later, the platform set off on its last voyage – and more world records were broken.

Published May 23, 2018   •   Updated April 14, 2020
© Norsk Oljemuseum
close Close

Building Statfjord C

person by Trude Meland, Norwegian Petroleum Museum
The Statfjord licensees appointed an action team in the early summer of 1978 to assess possible options for building the planned C platform. Completed in 1979, this study concluded that none of the options on offer provided a financially acceptable solution.
— Statfjord C was towed to the field in June 1984. Photo: Mobil/Norwegian Petroleum Museum
© Norsk Oljemuseum

Another project team was accordingly appointed by the licensees to consider alternative development solutions for the northern part of the field. This work was to take account of reservoir properties, safety, and operational and maintenance friendliness. But the main emphasis would be on simplifying equipment, reducing weight and optimising construction methods. The concept had to be cheaper than Statfjord B.

Variations on the table ranged from a subsea development to a two-platform solution. One question was whether Statfjord C should be a satellite to the A platform, with drilling capacity alone, or a separate structure with processing and storage facilities.

The first option was a combined drilling, quarters and water injection platform with a daily production capacity of 285 000 barrels. It would have a concrete substructure, but without drilling or loading opportunities.

Produced oil would be piped directly from the wellhead to Statfjord A for processing. The drawback was that this would not be possible until output began to decline on the A platform and spare capacity became available.

The second solution was an integrated production, drilling and quarters (PDQ) platform with water injection capabilities, which could process 180 000 barrels per day (b/d) and transfer a further 150 000 b/d to Statfjord A. This would be supported on a steel jacket, and the use of tankers for both storage and loading of crude was envisaged.

The final option considered in this round was a PDQ platform with 180 000 b/d in processing capacity. It would rest on a three-shaft Condeep concrete gravity base structure (GBS) with storage. Loading would use the buoys on Statfjord A and B.

Further studies of detailed estimates for costs and timetables were carried out with these variants until 22 January 1980, when the licensees decided on the third option – an integrated PDQ platform.

To benefit from both time and cost savings, Statfjord C was intended to be a duplicate of the B platform. But this was not achieved – it was only an approximate copy of Statfjord B. The differences were not necessarily easy to spot, but had great significance for production, safety and living conditions.

The biggest change was that the C platform was dimensioned to produce 210 000 b/d from 19 wells, compared with 180 000 from 15 wells on Statfjord B.

Since the gas processing train on Statfjord C had been completed when the platform reached the field, it became the first installation on the field to deliver to the Statpipe network running to Kårstø north of Stavanger and on to Emden in Germany via Ekofisk.

The most visible change was the helideck, which was elevated to avoid the wind forces and turbulence created by the drilling module on Statfjord B. Because the helideck on the latter was below the level of other structures, helicopter traffic to and from the platform had faced problems. When the wind was in a certain direction and stronger than a stiff breeze, flights could neither land nor take off. So the Statfjord C helideck rose high and free above the rest of the topside, as if on stilts.

c-plattformen, Bygging, utslep og oppstart,
The Statfjord C living quarter. Photo: Mobil Exploration Norway Inc./Norwegian Petroleum Museum

The size of the living quarters was also increased, from 200 berths on the B platform to 272. This was achieved by placing an extra storey of cabins on top, and moving the stairwells to the sides. An additional storey for ventilation equipment was installed above that again.

Seabed conditions at the northern end of the field, where Statfjord C was to be installed, were firmer than further south. This meant that the base of its GBS did not have to be as large as it was on B – 14 000 square metres compared with 18 000. The design of the steel skirts under the base was amended.

Since the plans called for a larger production capacity, the diameter of a number of pipes had to be increased. At the same time, the tanks for separating gas from oil were provided with new internal equipment to boost their efficiency.

Another type of gas dewatering facility was also specified. This involved a contractor pump to remove water from the gas with triethylene glycol, instead of injecting glycol into a heat exchanger. A similar system was later installed on both A and B platforms.

Other equipment made it possible to increase water injection rates to 296 000 b/d – and actually as high as 350 000 b/d if necessary – compared with 272 000 b/d on Statfjord B. In addition, ballast pump capacity was expanded. But the main structure and most of the equipment were indeed copied from the B platform.

Approved and initiated

The official approval given for Statfjord B also applied to the C platform, and the concept for the latter was approved in a letter to operator Mobil on 24 December 1980.

Norway’s offshore supplies industry was impatient to get going on the third Statfjord platform. Employment in the engineering industry was still down in 1979, and a rapid development was the only way to close the gap facing the Norwegian oil-related industrial sector.

After the licensees had resolved to build Statfjord C, however, rumours began to circulate of changes to petroleum taxation in Norway. The price of crude oil had risen sharply, and the Norwegian government wanted to capture more of the consequent profits. It planned to raise tax on these earnings from 70 to 80 per cent. Such schemes create problems.

International conditions provided the background for the rising prices. Put briefly, Egypt signed the Camp David accord in 1978. Iraq maintained that this represented a betrayal of the Arab cause, and only Saudi Arabia prevented Egyptian isolation at the Arab summit in November 1978.

The consequence was instead that the Saudi role in the Organisation of Oil Exporting Countries (Opec) was weakened. Its efforts to secure moderation on the issue of raising oil prices accordingly failed to win through at the Opec meeting in December. The organisation raised prices by 10 per cent during 1979.

This was paralleled by political unrest in Iran. The Shah’s position had been weakened since the autumn of 1978, and extensive strikes at Iranian petroleum facilities reduced production. Panic began to spread in western oil markets. The Shah was forced to leave Iran in January 1979 and Ayatollah Khomeini came to power two months later.

Iranian oil production continued to decline, creating uncertainty in the market. Opec failed to bring oil prices under control in the spring and summer of 1979, demand rose and spot prices reached new heights. High spot prices also prompted producers to demand supplements on the official price, which boosted their revenues. The Norwegian government wanted to secure its slice of these increased profits through higher taxes.
A number of the Statfjord licensees were unhappy at the thought of tax changes, and wanted to discuss a possible cancellation of the C platform. Mobil took the lead on these efforts.

Investment costs were weighed against income potential, and showed – according to Mobil’s calculations – that the new operating parameters imposed by the government would make the profitability of Statfjord C doubtful. Unless income for the Statfjord licensees was improved, Mobil would propose that the platform be dropped.

The shipyard crisis was still not over in 1980, and a refusal to build Statfjord C would have had serious consequences for jobs in Norway’s engineering industry. Some eight million working hours would be lost. The Federation of Norwegian Industries (MVL) accordingly supported Mobil and took contact on its own account with the Ministry of Industry. It feared that the new tax rules might prompt the postponement of construction contracts.

Opponents of the new tax argued that three platforms would make it possible to regulate production in a way which ensured optimum utilisation of all the installations and the whole field. For its part, the Ministry of Finance maintained that Mobil had failed to take account of the increased oil price in its calculations.

It nevertheless transpired that cross-party consensus prevailed on the tax changes. The main opposition parties – the Conservatives, the Christian Democrats and the Centre Party – found the increase reasonable and accepted the Labour government’s proposal to raise the tax on profits to 80 per cent. The Socialist Left and the Liberals would have been happy to go even further.

A decision on building Statfjord C was due to be taken by the Statfjord Unit Operating Committee (SUOC) in July 1980. Mobil was uncertain about support for its proposal to drop the platform, and proposed a test vote. This showed that the operator was the only opponent of building the platform.

Mobil did not want to be directly voted down, and proposed that the order of voting be reversed so that it did not have to cast a ballot first. Since the majority for building Statfjord C was binding, the operator abstained. Once the decision had been made, however, it tackled the job with great enthusiasm.

Compensation claims

The City of Stavanger was sued in 1980 by five homeowners in Hinnasvingen and Hindalsveien, who primarily wanted GBS construction operations in Hinnavågen to cease. They also demanded compensation of NOK 100 000 each for damage and nuisance, or up to NOK 20 000 per property per year for future problems.

The claimants alleged that they were subject to noise and intrusive illumination from the powerful spotlights used at night. Their view had also been destroyed.

While the court agreed that all the properties had suffered nuisance from the activity, this was not of any special character and could not be expected to be different if other industry had been located there. It could not be considered unreasonable. The judge found in favour of the city, and Condeep construction could continue. But the council was not awarded costs.

Since the city had clearly told the homeowners that the construction work was temporary and would not continue beyond 1978, the latter felt they had been misled when it became clear that the work was set to go on for many years.
Source: Stavanger Aftenblad

Constructing the GBS

Statfjord C Jåttavågen, Bygging, utslep og oppstart,
Construction of the concrete GBS began in the Hinnavågen dry dock. It was then towed out into the Gands Fjord for further slipforming. The job of slipforming the shafts began in January 1983. Really bad weather meant unpleasant conditions for the workforce as the shafts rose at a rate of three metres per day. Photo: Leif Berge/Equinor

Constructing the GBSNorwegian Contractors (NC) began work on building the concrete GBS for Statfjord C on 10 November 1980, before the contract had officially been signed, in order to employ personnel it wanted to retain. The sheet pile retaining wall was re-established by 1 December, and notifications issued to shipping in the Gands Fjord.

The NC contract was the first awarded for the Statfjord C construction project, and covered a four-shaft GBS. This structure was virtually identical to Statfjord B, with 20 oil storage cells forming its bottom section. Each cell could store 260 000 tonnes of crude.

NC needed 200 additional permanent employees, and 1 500 people would be working at the Hinnavågen facility during the most hectic phase when the shafts were slipformed. Schoolchildren and students once again had the chance to earn a few thousand kroner during the four weeks that this operation would take.

Installation of the steel skirts to ensure that the platform stood stably on the field started during January. NC’s design personnel only had a short time to do their work before construction began in the dock. Bottom conditions at the Statfjord B and C sites differed greatly, and a completely new base structure was required.

The computers used to calculate pressure, stress and other key conditions lacked the capacity that such machines now possess. It took them 12.5 days to conduct the global analysis ¬– the most extensive of the lot – covering stresses in the concrete.

Physical work in the dry dock could begin on 12 January 1981. Three years later, on 18 January 1984, after a three-day delay because of bad weather, the concrete structure could leave the Gands Fjord off Stavanger for Vats and mating with the topside.

Adding it all up

Bygging, utslep og oppstart,
Casting of the Statfjord C GBS. Photo: Norwegian Contractors / Norwegian Petroleum Museum

The concrete GBS had a base area of 12 800 square metres, and 24 cells with an internal diameter of 23 metres. These stood 64 metres high, with the exception of four which were extended as shafts to a height of 176 metres.

With a dry weight of 600 000 tonnes, the structure contained 13 000 cubic metres of concrete and 35 000 tonnes of reinforcement bars (rebars) – equivalent to five Eiffel Towers. 

In addition, the project went through three tonnes of coffee, 60 000 pairs of gloves, 3 000 crowbars, 12 000 rebar fixings, 5 000 plastic buckets and 4 000 spanners. But a new communication system meant that consumption of walkie-talkie batteries declined by 200 000 compared with Statfjord B.

The Statfjord C topside under construction at Rosenberg Verft. Photo: Mobil Exploration Norway Inc


Bygging, utslep og oppstart,
Engineers and designers from the Norwegian engineering company, Norwegian Petroleum Consultants, and the British Foster Wheeler, were engaged as consultants for the Statfjord C project. The blueprints were drawn on tracing paper. Photo: Leif Berge/Equinor

The main consultant for constructing Statfjord C was Norwegian Petroleum Consultants (NPC). This company had also worked on Statfjord B, but was now in partnership with Britain’s Foster Wheeler (FW).

A project service contractor (PSC) team was located in Asker outside Oslo. This had two main jobs. The first of these was to provide engineering design services, including work on the tender documents. Sending out such packages of drawings, material specifications and deadlines to be included in a tender was a big job. In addition came receiving, assessing and negotiating on bids and ultimately awarding contracts.

Second, the PSC was to make provision for purchasing equipment and services for the platform. Other tasks included making specialists available to the operator and cost controllers, keep accounts and award contracts. Totalling 340 people, the team comprised three Norwegians for every Briton.

Mobil also had its own staff of 50-60 personnel in Asker, including six from Statoil. This group was known as the project task force (PFT). Its job was to monitor work by the PSC and the other contractors, and to provide advice, conduct checks and issue approvals.

The project management job was simpler and less extensive than for Statfjord B. About 6 000 main and 5 000 detailed drawings were required for the C platform. Fifty per cent of these could be copied directly from the B drawings, 40 per cent had to be revised on the basis of existing documents, and only 10 per cent – a few hundred – of the main drawings had to be created from scratch.

Engineering design was divided among several contractors. NPC did about 60 per cent of the work, primarily on the topside modules and all electrical and installation design. Canada’s Triocean designed the drilling derrick and modules, and Moss Rosenberg Verft (MRV) did the cellar deck. Leirvik Sveis designed and built the living quarters.

Other contracts

The Statfjord group tried to achieve a wider distribution of the topside work on this occasion. It had the quarrel between Aker and MRV over the topside contract for Statfjord B fresh in its mind when putting the C platform out to tender.

But it was difficult for others to compete with MRV over the job, since it had developed a facility tailored for the B topside. Since Statfjord C would be very similar, the Kværner company was very strongly placed. Nobody else turned out to be interested, so the job of fabricating and hooking-up the steel topside went to MRV without competitive tendering.

If MRV was the only candidate for building the topside and its assembly and hook-up, competition was tougher for mechanical outfitting of the GBS shafts. Bids were submitted by NC itself as well as by Aker Contracting ¬– a newly established company which recruited personnel from all Aker group members – and the Kværner-Rosenberg Joint Venture (KRJV) between Kværner group subsidiaries MRV, Kværner Engineering and Kværner Brug.

An initial evaluation found that Aker had the lowest bid and NC the highest, thereby eliminating latter. But none of the bids were in the form Mobil wanted. A new round was held, and the KRJV maintained that it could make an improved offer after securing better terms for materials and services from sub-contractors. It reduced its bid by NOK 25 million.

Mobil was unsure whether this represented a genuine price reduction or an attempt to submit a new bid, and also gave Aker another chance. The two competitors submitted final bids with revised prices. Both had achieved substantial reductions – Aker by NOK 33 million and the KRJV by no less than NOK 72 million from its original bid. The latter accordingly won the job, but the real winners from the big price cut were naturally Mobil and its fellow Statfjord licensees.

Mechanical outfitting of the concrete shafts was performed by a joint venture between Kværner Brug in Oslo, Kværner Egersund and MRV’s Rosenberg Verft in Stavanger. These companies fabricated and installed 9 500 tonnes of decks and equipment in the shafts and cells. These structures were lifted into the GBS by the Ugland group’s Uglen crane ship.

Statoil called for an extraordinary meeting of the SUOC to discuss the assessment of bids for the module support frame (MSF). This was to be built in three sections – two ends and a centre piece. Five bids had been received from Kværner Egersund, Fredrikstad Mekaniske Verksted (FMV), a German yard and two in the UK.

The lowest prices were offered by Britain’s McDermott and Germany’s Howaldtswerke. Both Egersund and FMV were 20 per cent higher. Overall, this meant that the Norwegian yards were NOK 33 million more expensive.

Statoil nevertheless took the view that the Statfjord group should opt for the Norwegian fabricators, who had experience and would probably deliver on schedule. The issue was submitted to the Ministry of Petroleum and Energy, which refused to take a position. Statoil was forced to accept the lowest bids, and the work went to Germany and the UK.

Construction time for Statfjord C was extended by almost half a year compared with Statfjord B, from 30 to 35 months. That reduced the need for peak staffing, and day-to-day work became less hectic. Making the structure a virtual copy of the B platform meant that fewer drawings were needed, with less extra work for MRV, and allowed a number of smaller jobs to be contracted out to other fabricators when the company could not compete on price.

Statfjord C, engelsk, bygging, Bygging, utslep og oppstart
The Statfjord C topside under construction at Rosenberg Ship Yard. Photo: Mobil Exploration Norway Inc./Norwegian Petroleum Museum

While the construction contracts were virtually the same as for Statfjord B, they contained a built-in performance element. This was intended to encourage the contractors to reach clearly defined sub-targets and increase productivity by 15 per cent on all work to be done on a cost plus basis.

Building a close copy of the B platform yielded benefits. Work proceeded without problems throughout 1982, and the project was ahead of schedule by the end of that year. Forecasts looked even better towards the summer of 1983. Outfitting of the GBS was no less than three months ahead of schedule, and it could be delivered almost three weeks before the original contractual date in February 1984.

Overview of supplier

  • Project management: NPC and Foster Wheeler
  • Engineering: NPC (module deck, electrical, instrumentation), Triocean (drilling derrick and modules) and Moss Rosenberg Verft (cellar deck)
  • Construction concrete GBS: NC
  • Mechanical outfitting of GBS: Moss Rosenberg Verft in cooperation with Kværner Brug and Kværner Egersund
  • Topside construction and hook-up: Moss Rosenberg Verft
  • Fabrication of MSF: Howaldswerke, McDermott and Stord Verft
  • Living quarters: Leirvik Sveis

In addition to these main contractors, deliveries and equipment came from about 250 different companies worldwide.


Kostnadsanalysen norsk kontinentalsokkel: report from the management group appointed by royal decree of 16 March 1979, submitted to the Ministry of Petroleum and Energy on 29 April 1980.
Norsk Oljerevy. (1980). no 6. Mobil: Statfjord C fremdeles uøkonomisk.
Norsk Oljerevy. (1983). no 12. Statfjord C – 800 000 tonn stål og betong.

Published May 23, 2018   •   Updated March 26, 2020
© Norsk Oljemuseum
close Close