by Finn Harald Sandberg, Norwegian Petroleum Museum
Scrapping old platforms from the Greater Ekofisk Area (GEA) has created new jobs in both Norway and continental Europe since the mid-2000s. Redundant GEA installations were removed to shore every single summer season from 2005 to 2021 in a total number of 14 installations
— Removal of the Tank's topside. Photo: Kjetil Alsvik/ConocoPhillips
It began with the topsides on the Ekofisk tank. That job lasted until May 2007, and was then followed one after the other by the steel Ekofisk I platforms which were to be taken away.
In Norway, an industrial site at Nedre Vats in Vindafjord local authority north of Stavanger began the breaker’s yard and recycling facility for these redundant facilities. Petroleum and energy minister Torhild Widvey performed the official opening of this AF Decom yard on 18 August 2005. It lay in the same place where Norwegian Contractors had mated its Condeep concrete platforms.
Et enstemmig kommunestyre i Vindafjord hadde til tross for protester fra beboere og bedrifter, miljøorganisasjoner og fylkeskommunen mot støy, giftutslipp i sjøen og rasering av kulturminner, godkjente reguleringsplanen. A unanimous local council had approved the new use of the site – despite protests from residents and companies, environmental organisations and the county council over noise, toxic discharges to the sea and destruction of cultural relics.
According to chair Arne Bergsvåg from the farmer-oriented Centre Party, the council was also against toxic discharges to the fjord. But he believed that frequent inspections and tougher requirements on discharge volumes would ensure that the business was carried on in an acceptable manner. “However, we can naturally never safeguard ourselves 100 per cent,” he admitted. A strong argument for the council was that the yard would employ about 150 people over a long period.[REMOVE]Fotnote: NTB, 19.12.2007, ”Vindafjord blir gravplass for oljeplattformer”.
Tank topsides first – 2005-08
Totalling some 26 000 tonnes, the steel superstructure on the Ekofisk tank led the way in the removal programme and 18 people from AF Decom made preparations there from the spring of 2005. This work was stepped up in September, with 40 of the company’s employees at work offshore. The first excavators equipped with hydraulic shears had arrived in June.
These machines “ate” their way through the superstructure, and sorted the remains roughly into containers. Such an operation had never previously been done offshore.
No less than 24 500 tonnes of shredded material, mostly steel, were loaded into supply vessels for shipment to the recycling yard at Vats.
The waste was then sorted and further processed and checked before being transported for smelting and possible deposition. The recycling ratio was no less than 98 per cent.[REMOVE]Fotnote: Pioner, nr. 3 2008.
Removal work on the tank was over by the end of 2007, with onshore disposition finished the following year. A total of 2 800 containers had then been sent ashore in 108 shipments. That left only the concrete structure of the tank with its “20-metre” deck and part of “30-metre” deck visible. An era in Norwegian oil history was over, and the Ekofisk seascape had been altered for ever.
Dismantling nine platforms
Dutch installation, heavy lift and subsea specialist Heerema Marine Contractors (HMC) had the main contract with AF Decom Offshore as organiser of the work before removal and deposition on land at Vats. This job covered the removal of nine Ekofisk I platforms, with an option for another four. AF Decom had the main contract for removing the Ekofisk tank topsides.
The dismantling work carried out by HMC ran for five years from 2009 to 2014. It was worth NOK 1.2 billion, including options.[REMOVE]
Fotnote: NTB, 18.06.2008, “Milliardavtale om fjerning av plattformer”.
Platform removal on Edda in 2006
The first field to have its lighter structures removed as part of the cessation project was Edda, 13 kilometres south-west of Ekofisk, and involved the flare stack, bridge and bridge support.
HMC used Thialf – one of the world’s largest crane vessels – for this operation. Its work deck alone is bigger than two football pitches.
With more than 260 personnel on board, it resembles a large, well-organised anthill with people working everywhere between containers and heavy lifting gear. The heaviest Edda lift was 750 tonnes, which could almost be considered a fleabite for Thialf with its crane capacity of no less than 14 000 tonnes.
“It’s important for us to harvest experience now,” explained Dag Roar Johansen, ConocoPhillips’ project manager. “This operation has been very successful.”[REMOVE]Fotnote: NTB, 26.06.2009, “Skal fjerne Norges første plattformer”.
Each lift called for unique plans and special adjustments to ensure that it was carried out safely and in an environment-friendly manner.
Removing the bridge support presented a particular challenge on Edda. A cutting tool utilising sand and water under high pressure was lowered inside the structure. This allowed its piles to be cut 2.5 metres below the seabed so no obstacles to future maritime activities were left. The operation was viewed with some trepidation because it demanded good weather and free access for the cutting equipment to the necessary depth between the seabed.
Another critical operation involved lifting the support and turning it through 90 degrees in order to place it horizontally on a barge. A work platform was installed on top, with new pad eyes welded on for attaching steel ropes. Fixing one of these low down on one leg presented particular difficulties. This was done while the support hung from the crane. When the pad eyes was ready, strong ropes were used to attach it to the other crane.
The operation was completed with both cranes lifting in tandem, turning the support and placing it on the barge. Once all the structures were attached to its deck, this vessel could sail for Vats.[REMOVE]Fotnote:Pioner, “Lette strukturer fjernes”, ConocoPhillips, August 2006.
Removing light structures in 2007
Four removal projects were pursued with light structures in the GEA during the summer of 2007, starting in June with the removal of flare stack, bridge and bridge supports from Albuskjell 1/6 A. This job utilised the Hermod crane vessel, which had a lifting capacity of 8 100 tonnes and more than 250 people working on board.
The next job was at the Ekofisk Complex, where the northern flare stack with associated bridge supports and bridges on the north side of Ekofisk 2/4 R were removed.
Finally came the light structures on the Cod 7/11 A platform. All the steel from these removal operations was transported by barge to AF Decom’s yard at Vats.[REMOVE]Fotnote:Pioner, no 5, “Fjerning av lette strukturer”, ConocoPhillips, June 2007.
Pipeline pumping stations removed, 2009-10
In the 2009 summer season, the giant crane on Thialf had the job of lifting away redundant installations and bridges which isolated the Ekofisk tank from the rest of the Ekofisk Complex. The vessel was also involved in making safe on 2/4 W and removing sections from this platform after a ship had collided with it in June of the same year. During September, fellow HMC crane vessel Hermod completed the job of removing the topsides from the two pumping platforms in the UK North Sea.
The 37/4 A and 36/22 A structures stood along the oil pipeline which ran from Ekofisk to Teesside in north-east England. Their topsides were taken ashore for recycling.[REMOVE]Fotnote:Pioner, no 6, “Fjerning fortsetter neste sommer”, ConocoPhillips, 2009.
Thialf, the bigger of the two ships, then arrived to remove the jackets for these two platforms. In both cases, it took the structures to a breaker’s yard at Mekjarvik outside Stavanger. They were split in two there, with the lower part transported on to the recycling facility at Vats by barge, while the crane ship carried the upper section to the same destination.[REMOVE]Fotnote:Pioner, no 4, “Sluttdisponering Ekofisk I”,» ConocoPhillips, 2010.
Big tonnages shipped away in 2010-11
Crane vessels carried no less than 25 000 tonnes of platform components to Vats during May-August 2010, with Hermod discharging at the yard for the last time at the end of July. That final consignment included the remaining modules from Albuskjell 2/4 F and half the module support frame (MSF) for that platform. This was one of the two installations which had stood on Albuskjell and had been on stream until 1990. Its jacket was removed the following year.
Hermod was in action on Edda 2/7 C and West Ekofisk 2/4 D to make them safe and prepare to remove their topsides and jackets in 2011 and 2012 respectively.
Thialf finished its 2010 work at the end of August, with a final lift carried out at the Ekofisk Complex with the jacket for the 2/4 R riser platform.
The 2011 summer season began as early as mid-April, when Thialf left the Åmøy Fjord near Stavanger en route for Ekofisk. It remained in action until mid-August. During that period, it made six round trips between the GEA and Vats. The total amount removed amounted to roughly 25 000 tonnes – roughly the same as the year before.
The work programme began with making safe on Cod 7/11 A, followed by removal of the large and complex topsides from Edda 2/7 C. Thialf had to make two round trips to Vats with modules weighing a total of 11 000 tonnes.
Removing the topsides from West Ekofisk 2/4 D was the next assignment, before the vessel turned to Albuskjell 2/4 F to take away its jacket. Because of its size, the latter was divided horizontally into two sections before transport.
New heavy lifts in the summer of 2012
Thialf and fellow crane vessel Balder continued the GEA removal operation during the 2012 summer season, with Balder starting to prepare the Edda 2/7 D and West Ekofisk 2/4 D jackets in mid-June. After delivering half the MSF from Edda 2/7 D to Vats in July, this vessel began lifting off the Cod 7/11 A topsides. Seven modules had been removed by 31 July. Mobilised in July, Thialf started by lifting the remainder of the MSF on Edda 2/7 D and the top half of its jacket onto the deck. It then raised the bottom section and sailed for land with that structure hanging from its crane. Delivery was made to Vats by the end of the month. Thialf then returned to Edda 2/7 C in order to remove the jacket, and was back in Vats on 10 August to deliver the upper section of this structure. It finished by taking away the bottom part of the 2/7 C jacket.
Summer 2013 – lifting campaign completed
The lower part of the Albuskjell 1/6 A jacket had the honour of completing the lifting campaign for the summer season of 2013. That meant the last of nine agreed installations was gone.
Tialf mobilised at the end of August, and started with the Cod jacket before moving on to the 1/6 A structure. That was so large it had to be transported in two stages.
The final delivery to Vats was on 22 September. Earlier that summer, the Albuskjell platform’s topside had been taken ashore. Some 25 000 tonnes were removed that year as well.
“With this year’s campaign, we’ve reached an important milestone for the company,” said Johansen. “We have then fulfilled our commitment to the government to remove these nine platforms [37/4 A, 36/22 A, 2/4 R, 2/4 P, 2/4 F, 2/4 D, 2/7 C, 7/11 A and 1/6 A] by the end of 2013.” Ekofisk I had really become history – and its individual components had been recycled for new applications.
Season eight – 2014
Two accommodation modules were removed by HMC from the 2/4 Q platform in the Ekofisk Complex during July 2014 and taken to Vats for scrapping.
When operational in 1974, this platform had been the first permanent accommodation platform in the Norwegian North Sea. It served for an impressive 30 years – admittedly with two extensive module replacements to meet new working environment requirements.
The jacket for Ekofisk 2/4 S and the bridge support were also removed on the northern side of the complex. Statoil led this work on behalf of Gassco, which owned the structure, while ConocoPhillips provided technical backing.
The very last lift in this major campaign was the bridge linking the tank with Ekofisk 2/4 G, which had been shut down in 1998. ConocoPhillips again gave technical support to operator BP.
That year’s activities again went according to plan and with good safety results, Johansen reported in an interview with house journal Pioner. “Excellent collaboration with the operations organisation on land and offshore as well as good follow-up by our own team have been the key to such execution,” he said. In the course of eight years, 130 000 tonnes of steel had been removed from the GEA without serious threats to life or health – a unique operation.
Planning and implementing the removal of these platforms and pipelines was a technical and organisational achievement on a par with the big development projects off Norway.
But the story does not end there. The Ekofisk 2/4 A, 2/4 H, 2/4 Q and 2/4 FTP installations have later been removed between 2017 and 2021. The total number of installations removed from Ekofisk was 14 in 2022.
Åm was born at Årdal in the Sogn district of western Norway in 1944, and grew up in Oppdal and Volda/Ørsta where he proved an able pupil at school.
He opted to study mining engineering at the Norwegian Institute of Technology (NTH) in Trondheim, graduating with honours in 1967.
Åm’s first job was with the Norwegian Geological Survey (NGU), again in Trondheim, where he worked and conducted research for six years.One of his jobs was to interpret aeromagnetic measurements of sub-surface rocks made from the air, which provide valuable information on geology and prospects for finding petroleum.In a series of publications, he described the big sedimentary basins identified in the Skagerrak between Norway and Denmark and in the Norwegian and Barents Seas.
He joined the Norwegian Petroleum Directorate (NPD) in 1974, serving as a section head in the resource department and a principal engineer in the safety department.
That was followed by three years with Statoil, where he became the state oil company’s first vice president for research and development.His appointments at the time included chairinga research programme on offshore safety, which led to legislation enacted by the Storting (parliament) and a bigger research effort.
Åm secured a job with Phillips in 1982 and was soon sent to the head office at Bartlesville in Oklahoma to get better acquainted withthe company and its corporate culture.
After a year in the USA, he returned to thecompany’s Tananger office outside Stavanger and became the first Norwegian to serve as offshore manager for the Greater Ekofisk Area (GEA).
That put him in charge of 23 platforms, with responsibility for the waterflooding programme as well as the project to jack up a number of the installations.These major developments extended the producing life of the GEA and sharply increased estimates for recoverable reserves from its fields.
Åm led this work during difficult times, with low oil prices and the need to implement cost savings and overcome substantial financial challenges.As if that were not enough, he also taught at the University of Bergen from 1985 to 1990 as an adjunct (part-time) professor of applied geophysics.
First Norwegian chief executive
After heading operations in the Permian and San Juan Basinsat Odessa, Texas, from 1988-91, Åm became the first Norwegian president and managing director for Phillips Petroleum Norway.
That put him in charge of 3 000 employees in the GEA as well as in Tananger, Oslo, Teesside and Emden. This was when a redevelopment of Ekofisk was planned, along with the future cessation and removal of old platforms.[REMOVE]Fotnote: https://www.fylkesmannen.no/globalassets/fm-rogaland/dokument-fmro/felles-og-leiing/brev-og-artiklar/fm-tale-til-knut-am.pdf
By 1996, Åm was back in Bartlesville – now as vice president and head of all exploration and production in Phillips. He stayed in that job until retiring in the USA during 1999.
Offices and committees
But his working life did not end there. Appointments from 1999 to 2007 include membership of the Statoil board – and many similar posts can be mentioned.
Åm has been president of the Norwegian Geological Council and the Norwegian Petroleum Society, and chair of the Norwegian Oil Industry Association (now the Norwegian Oil and Gas Association).
He led the exhibition committee of the 1996 ONS oil show in Stavanger, and has chaired Bergen’s Christian Michelsen Research institute as well as the industrial council of the Norwegian Academy of Science and Letters.
In addition to chairing Hitec ASA, he has been a director of several technology companies.
Mention must also be made of the improved recovery committee appointed by the Ministry of Petroleum and Energy with Åm as chair.This produced a report in September 2010 which presented 44 specific measures for improving the recovery factor on the Norwegian continental shelf (NCS).
Through his work and many appointments, Åm has been acclaimed fora combination of expertise, creativity and determination. He also demonstrated the ability to tackle the requirements of Norway as a nation as well as the industry and its employees – not least with regard to the working environment and safety in a demanding and risky offshore industry.
In retirement, Åm is an optimist – with regard to the climate as well. “I’m very concerned with nature, but believe we should extract the resources it’s given us,” he told Otium in 2016.
“Norway could have a long and good future in the oil and gas industry if people give it more support. Exploring for new deposits is important, but we should also seek to achieve a far better recovery factor from both new and existing fields.”
“You can naturally concentrate on life’s negative aspects. Then everything’s simply awful. I think you’ll be a far happier person if you prefer to see the positive side of life. I call that self-motivation. We need more of that in the energy sector.”[REMOVE]Fotnote: https://api.optimum.no/sites/default/files/PDF/optimum-magasinet-2016.pdf
Published 21. October 2019 • Updated 21. October 2019
Kjersti Melberg, Norwegian Petroleum Museum. Based on an interview with Kristensen on 12 September 2019.
More than forty-five years of service on Ekofisk underpin Knut Ove Kristensen’s status as a pioneering leader on the Norwegian continental shelf (NCS). His involvement began in 1974 when he switched from a career at sea to become a process technician for Phillips Petroleum.
— Knut Ove Kristensen in conversation with process apprentice Fredrik Svindland Theissen (left) and operations manager Siri Friestad. Photo: ConocoPhillips
Early promotion and trust followed, and he served as an offshore installation manager (OIM) for more than 33 years in the Greater Ekofisk Area.
Kristensen recalls that he was a committed young man in the early 1970s – an open, curious and plain-speaking person who was not afraid to criticise health, safety and environmental (HSE) conditions.
The working style he encountered offshore suited him well, ready as he was to speak his mind. “I’ve undoubtedly been a loud-mouth. I’m used to having zealous people in the Family With grand-parents and a father who served as mayors, which is perhaps why I don’t quite know when to keep quiet.”
Thinking back to working conditions when he started in petroleum industry, he recalls living on Gulftide, Norway’s first production facility, and says it was fascinating.
“This was an old jack-up rig, with the helideck installed on planks. We were four to a cabin, and things were pretty shabby. Primitive conditions prevailed, to put it mildly.”
The workplace at the time was characterised by the presence of the Americans, and confusions frequently arose between them and those who were not particularly good at English.
“It was very unusual,” reflects Kristensen. “We were trained up by the Americans, of course – they were the ones who knew about this business.There were a lot of misunderstandings among the Norwegians, people who pretended to understand the messages they were given about what jobs to do. Both serious and funny situations occured. Those of us who’d been to sea undoubtedly had an advantage in that we knew the language a bit better. The rest were fishermen and smallholders and ordinary people from the Districts in Western Norway who didn’t speak much English. Offshore terminology wasn’t easy for people who didn’t have the language.”
He quickly grasped the ethos in this working environment. “The Americans often only gave you one chance. If you showed that you could cope withyour job, you won trust, new opportunities and more responsibility.”
Given his background in the Norwegian merchant marine, however, Kristensen reacted negatively to a number of the conditions which prevailed at the time.“I was one of the youngest then, and that wasn’t always easy because there were a number of older and more experienced people who felt they had a ‘monopoly of brains’,” he comments. “And quite a lot were pushy.“Working conditions weren’t orderly, with proper employmentcontracts like I was used to from my time at sea thanks to the Norwegian Seamen’s Union – unionisation and the like.”
He adds that he is grateful for everything he learned from the Americans, but that they at the time were not particularly keen on unions and the Norwegian concept of collaboration between employers and employees.“They thought it was enough to enter into agreements on a man–to–man basis or with the company, and saw no need to organise this via trade unions.”
Given his views, it is not surprising that he became involved at an early stage with the Ekofisk Committee by serving as secretary to Øyvind Krokvik, who was first head of this union.
Kristensen explains that he has been committed throughout his career to involvement and worker participation and to good collaboration between unions, the safety service and management.That was particularly important during the early years of the petroleum industry on the NCS, he emphasises. His experience of union work accompanied him into various senior posts on Ekofisk.
With a gleamin his eye, he says the following about his promotion: “Acquiring managerial responsibility early on may have had something to do with my involvement with the union.“Putting in place systems for worker participation and collaboration was particularly important in the early years of Norway’s offshore industry.
“I played a part in establishing the parameters which govern industrial relations out on the field today, with unions and the safety delegate service.
I became the country’s youngest OIM at the age of 24, and served as a manager out there for 41 years.
They may have thought ‘he’s more trouble than we need, so we’ll just promote him up and then be quit him’.”
Kristensen reports that he has been preoccupied throughout his managerial career with ensuring that “things are genuine” – that a manager must understand and personally be part of “the home team”.He explains that as the ability to understand a position from the standpoint of the various parties involved, and adds that he has thrived offshore with a living and working community.This he defines as one “where you get close to people, where everyone is seen and heard, and where they understand that they play an important role in reaching a common goal”.[REMOVE]Fotnote: Pionèr, ONS 2018: 8.
It did not take him long to learn how to adjust his management style to the offshore environment, but admits that this approach has developed over the years.“The leadership culture which dominated on the platforms during the early years undoubtedly influenced me a bit. I was probably very inflexible and saw things in black-and-white, but have become more judicious and considered over time.
“Nobody left my office earlier in any doubt about what I meant. I thought that saved a lot of time. But I can’t have been too bad, or I wouldn’t have held down the job for so long.”
Kristensen’s long service makes him uniqueon Ekofisk, and he has thought a lot about management. His expressed strategy has been to get people on side over HSE through commitment and integrity – and without any “second agenda”.
“Working in the Ekofisk Complex with 600-700 people is an unusual experience,” he observes. “I held the same job as the man in charge for 20 years. “That means you’re ‘on stage’ the whole time, and attend 10-12 HSE meetings every week. You’ve got to get people committed, drive a doctrine and sell a message.”This involves getting what people have to concentrate onimplanted in their hearts and minds so they can contribute to their own safety and that of others, he explains.
“You must be genuine, and your own integrity must be order. You have to build trust, and not least display respect for your audience.”
“What’s been a powerful help for me is that I’m on the home team. I’ve been a skilled worker myself and have been through most things.”
Kristensen emphasises several times that he regarded the unions, their elected officers and the safety delegates as a resource in this work.
“The tripartite collaboration pursued in the petroleum industry between government, companies and unions functions very well,” he concludes.“This is about informing and involving people, and ensuring that decisions aren’t taken over their heads. Our company has achieved that in a positive way.”
“The fact that Ekofisk is a mature field and ConocoPhillips is a mature company also has something to do with it. Cooperation with the Petroleum Safety Authority Norway and other authorities is also very good.”
Kristensen denies that union-management collaboration has become more strained during the downturns experienced by the petroleum industry.“Strained and strained – we must adjust to external conditions and try to protect thejobs needed tosafeguard the industry. But nobody’s ever been made redundant by this company. That’s worthy of respect. “
“Downsizing has been solved with severance packages. People have often been given early retirement. From that perspective, it’s been a privilege to work for an operator company.”
After almost 46 years with the company, Kristensen’s commitment to continuous improvement, good safety and high production regularity is as strong as ever.Recognising that substantial progress has been made in the HSE area over the years he has worked in the industry, he affirms that this issue is closest to his heart.
“We’ve staked out the path as we’ve advanced. We don’t accept incidents and accidents. We take a completely different approach to risk today. Accidents which do occur are used for all they’re worth in aneffort to say to ourselves: ‘this has actually happened, but it’s our duty to learn from it’.”
Kristensen has personally experienced accidents and injuries at close hand, and thereby knows the importance of preventive safety work to protect people, the environment and equipment.
He will never forget some incidents – and immediately mentions the Alexander L Kielland disaster in 1980 With 123 casualties. An article in local daily Stavanger Aftenblad as recently as 2012, with photos of all those who have died on duty on the NCS since 1966, made a big impression on him.
Britain’s Piper Alpha explosion in 1988, when 169 people were killed, is another major incident he recalls. His conclusion is that the petroleum sector has not been a Promised Land for all.
The former OIM proudly mentions a number of HSE improvements which have partlybeen the result of technological advances in the industry during his time.But he warns about hazards which still exist, such as vessels drifting out of control. A well-known incident on New Year’s Eve in 2015 made a particularly strong impression on him.
A 150000 tons, unmanned barge had come loose and was threatening to collide with installations on Ekofisk. Several hundred workers from this field and neighbouring Valhall were flown to safety and production was shut down.The barge passed the platforms at a distance of about one nautical mile, but Kristensen found the actual incident and the threat it posed frightening.
“Drifting vessels which come loose in rough weather, which can get pretty challenging out there, are perhaps the biggest hazard we now face. Luckily we have good procedures to handle such challenges.”
Such incidents and near-misses are regarded by Kristensen as a reminder that the petroleum industry is under an obligation to learn the necessary lessons.He points to the potential for learning from other industries, and emphasises the good collaboration which prevails across the company. Mechanical handling provides a good example, he says.
“Things can go terribly wrong. After fatal accidents in the 2000s, we established a work group which held monthly meetings. I took part as technical manager for these facilities.We involved everyone in the logistics chain on land, at the base and on the platforms. That attracted so much attention and such great improvements that we’ve now managed to prevent virtually all undesirable conditions in this area.”
Despite good systems and routines, colleagues on the installations are Kristensen’s most important reminder of the responsibility he has had as an OIM on Ekofisk.
“Experiences frommy early years meant that I have become particularly attentive to HSE – and I was involved in quite a lot, of course.But this mostly relates to the individual who gets injured on your watch and on your shift – in other words, the people you work with.They stood on the drill floor and worked so that the sparks flew around their ears. Having only two-three fingers used to confer ‘status’.”
He notes that improvements have a lot to do with technological progress. Much risk has been eliminated by automating a great deal of the work which used to be done manually.
“But we still have more than enough opportunities to injure ourselves. This has a lot to do with awareness – being present in the real world, making sure you’re focused. That’s actually expected for 12 hours at a time.”
A respectful attitude to his big responsibilities and duties was maintained by Kristensen to his last working day. “Emergency preparedness is like being at war – you do what you’re told.But you feel it. Although we’ve trained so long at this, you’re still conscious of being responsible for several hundred lives. Taking a wrong decision could …You must act on the basis of the information you’ve got, not what you know many months later. When you tackle it, however, you get a sense of mastery at solving the problem together with an outstanding emergency response organisation on land.Ultimately, though, you’re the skipper on your own ship.”
Time to reflect
Kristensen has finally retired from ConocoPhillips, giving him time to reflect over his own commitment and lifestyle offshore as it affected him and his family.
“For my own part, I must say that it’s had a price,” he admits. “I couldn’t get involved in politics or organisations, for example. I was only at home half of the time. I followed up the kids when I was at home, of course, but never felt I could be active in associations and so on, contribute the way I’d have liked.”
He has found the transition to retirement unaccustomed in many ways. “Simply remembering that I’m not going offshore is a big change, for example.I had to deal with so many challenges right up to my last day at work that it’s been impossible to prepare anything. I ought to have thought about and planned retirement a bit better, of course, but I’ll undoubtedly find something to do when I want to.”
Published 21. October 2019 • Updated 25. October 2019
The aim of this facility – an extension to the Ekofisk South project – was to increase waterflooding on the southern flank of the Ekofisk reservoir in order to maintain oil and gas production.
An amended plan for development and operation (PDO) of Ekofisk South was approved by the Ministry of Petroleum and Energy on 7 September 2017.
This involved installing a new seabed template with four water injection wells, and represented a continuation of the well-established Ekofisk production strategy based on waterflooding.[REMOVE]Fotnote: https://www.regjeringen.no/no/aktuelt/okt-utvinning-pa-ekofiskfeltet/id2570011/.
The template was installed in September 2017, with a technical solution similar to that used on the seabed facilities already installed – Ekofisk 2/4 VA and 2/4 VB.[REMOVE]Fotnote:Pionér, no 2, ConocoPhillips, 2018.
In addition to the structure itself, including wellheads and Xmas trees, the installation comprised control modules with umbilicals connected to the existing waterflooding system.
The 2/4 VC facility receives injection water from Eldfisk 2/7 E, while power and control signals come from Ekofisk 2/4 M. It is run from the Ekofisk 2/4 K control room.
When fully developed, overall injection capacity for this subsea installation will be 80 000 barrels per day through the four wells.
The water pipeline and umbilical to 2/4 VB were extended to 2/4 VC. Well operations on the latter began on 24 May 2018 with a view to starting injection before the end of the year.
Published 15. October 2019 • Updated 15. October 2019
Different systems for rotating personnel between work and leisure functioned in parallel on the drilling rigs during the early years of oil exploration in the Norwegian North Sea. The most common practice was nevertheless one week on and one off. To get a holiday, people carried on working offshore until they were entitled to three weeks free in one go.
However, this arrangement proved impractical – particularly for workers who going offshore or returning home on a Saturday or Sunday. They never got a full weekend off. To stagger such change-overs, the schedule was extended to eight days offshore with eight days free. One work period in five was also dropped, so every fifth free spell was 24 days long.[REMOVE]Fotnote: This gave a working time which averaged 38 hours per week and 1 824 hours per year after holidays. That corresponded to shift work on land.
When Norway’s Working Environment Act (WEA) came into force in 1977, the permitted length of a continuous shift on land was cut. But there was no assurance that this would be applied offshore. In its original form, the Act did not permit the 12-hour working day normal on all offshore installations. So amendments were needed to adapt the legal provisions to fixed platforms.[REMOVE]Fotnote: The Act specified that working time was 36 hours over seven days for work carried out around the clock throughout the week. That represented 1 877 hours a year on average. Adjusting this for four weeks of holiday gave a net working time of 1 733 hours.
The Norwegian Petroleum Directorate argued that reducing working time offshore was impractical, with the “special character” of the oil industry requiring exemptions.[REMOVE]Fotnote: Ryggvik, H, 1999, “Fra forbilde til sikkerhetssystem i forvitring: Fremveksten av et norsk sikkerhetsregime i lys av utviklingen på britisk sokkel”, Working Paper, Volume 114, Centre for Technology and Culture, University of Oslo, printed edition. Oslo: Centre for Technology, Innovation and Culture (TIK), University of Oslo: 16. As early as 1975, however, Ekofisk operator Phillips Petroleum had agreed to working hours for its own personnel which accorded with the provisions proposed for the new Act. A royal decree of 9 July 1976 extended the existing Worker Protection Act, with certain exceptions, to the fixed installations offshore on a temporary basis.
The WEA was then applied to these facility in 1977.[REMOVE]Fotnote: Ryggvik, H, 1999, “Fra forbilde til sikkerhetssystem i forvitring: Fremveksten av et norsk sikkerhetsregime i lys av utviklingen på britisk sokkel”, Working Paper, Volume 114, Centre for Technology and Culture, University of Oslo, printed edition. Oslo: Centre for Technology, Innovation and Culture (TIK), University of Oslo: 18. This meant that offshore workers had their working time regulated and acquired legal safeguards against unfair dismissal. After long discussions, the North Sea schedule was by and large established as two weeks working offshore and three weeks free on land.
But the WEA was not applied to floating units such as rigs, and working time in that part of the oil industry continued to be regulated by Norway’s Ship Labour Act.
An extra day
Norway’s legislation on paid holidays was amended in 1981 to give everyone a legal right to four weeks and one day off. The latter was nicknamed the “Gro Day” after Gro Harlem Brundtland, the Labour premier of the day. This meant the two weeks on/three weeks off schedule now imposed too many working hours. It was decided that the extra would be compensated as 25 hours of overtime per year.[REMOVE]Fotnote: Working time was reduced from 1 752 to 1 727 hours.
Agreement was reached in the 1986 collective pay negotiations on a 7.5-hour normal working day and a 37.5-hour week. Personnel both on land and offshore working a continuous shift also had their weekly hours cut 33.6.[REMOVE]Fotnote: Net working hours after deducting holidays were reduced from 1 752 to 1 727. To comply with these new terms, the offshore schedule was altered to two weeks at work, three weeks ashore, two weeks at work and four weeks on land.
When the Gro Day was introduced in 1981, the Labour government originally proposed introducing a full week’s extra holiday in stages over three years. But that failed to materialise. In 2000, the Norwegian Confederation of Trade Unions (LO) proposed a fifth holiday week for all employees, which would thereby reduce the number of hours in a work-year.[REMOVE]Fotnote: That involved an additional four free days of 7.5 hours offshore (32 hours). The hours to be worked were then reduced from 1 612 to 1 580. That demand was accepted, and most workers could thereby enjoy five weeks off. This naturally had consequences offshore, but implementing it there was not a straightforward matter.
A schedule of two weeks at work and three/four weeks at home had been 19 hours short of a normal work-year. That was overcome by deducting this time from pay or leaving the first 11 hours of overtime unpaid.[REMOVE]Fotnote: Sande, Leif, “Arbeidstiden på sokkelen”, Sysla – meninger, 11 March 2015.
The new holiday deal meant that an offshore worker would be doing 12 extra hours per year. This was initially paid as overtime, which the unions found unsatisfactory. They demanded the full holiday entitlement awarded to everyone else through the introduction of a schedule of two weeks on and four off. In 2002, the Norwegian Oil Industry Association (OLF – today the Norwegian Oil and Gas Association) allowed local deals under the offshore agreements to adopt this two-four scheme. All the companies subject to these agreements introduced the new schedule. ConocoPhillips was among the operators to do this, in its case covering the Greater Ekofisk Area.
However, the two-four system meant workers were falling short of a work-year by 122 hours.[REMOVE]Fotnote: Working 12 hours a day for 14 days, followed by four weeks off, means that an employee works 168 hours every six-week period. That adds up to 1 460 hours per year. Annual pay was thereby cut by 7.71 per cent to take account of the reduced time worked.[REMOVE]Fotnote: Norwegian Official Reports (NOU) 2016:1, Arbeidstidsutvalget — Regulering av arbeidstid – vern og fleksibilitet. https://www.regjeringen.no/no/dokumenter/nou-2016-1/id2467468/sec16. Other conditions were also set on Ekofisk. The whole offshore organisation was to be reviewed to find efficiency gains, and the agreement specified that the change would not lead to an increase in the workforce.[REMOVE]Fotnote:Pioner, “2-4-ordningen innføres”, March 2003.
Published 21. October 2019 • Updated 21. October 2019
This platform rests on a steel jacket built by Dragados at Cadiz in Spain. The module support frame (MSF) and topsides were fabricated by Energomontaz at Gdansk in Poland and completed at Kværner Egersund.
The topsides were installed in July 2013. Petroleum and energy minister Tord Lien performed the official inauguration of 2/4 Z and the Ekofisk South project on 29 October 2013,13 just four days after the platform came on stream.14
No control room is provided on 2/4 Z, but it has a local equipment room (LER) which is not permanently manned. The platform is monitored and remotely controlled from the control room on Ekofisk 2/4 J, but can also be run from the operations centre in Tananger.
by Gunleiv Hadland, Norwegian Petroleum Museum
The 2/4 VB subsea installation began injecting water in May 2013, three kilometres south of the Ekofisk Complex. It formed part of the Ekofisk South project approved by the Storting (parliament) in 2010.
Ekofisk 2/4 VB was a part of the Ekofisk South project
Producing May 16. 2013
Also called “Victor Bravo”
— Ekofisk 2/4 VB (Victor Bravo) lowered into the sea. Photo: Bob Bartlett/ConocoPhillips
So successful had the 2/4 VA facility proved to be that it was copied for 2/4 VB as an eight-well template, also delivered by FMC at Kongsberg.
Similarly, the wells on 2/4 VB were drilled by Maersk Innovator. The well operation department completed installation of the template, manifolds and casing for the eight subsea wells.
Seabed installations carried out by Subsea 7 comprised a five-kilometre pipeline for water from the Eldfisk Complex as well as a diver-installed T piece welded into the existing pipeline from Eldfisk 2/7 E to Ekofisk 2/4 K.
This assignment also covered laying three kilometres of umbilicals combining hydraulic lines and fibreoptic cables from 2/4 VA, so that 2/4 VB could also be remotely operated from land.
Published 23. September 2019 • Updated 7. February 2020
Known as coccoliths, these plates are so minute than 30 of them laid side by side would be no wider than a strand of hair. But what they lack in size, they make up for in numbers.
Their colossal accumulation is helped by the fact that coccolithophores reproduce asexually. When one dies, its coccoliths sinks to the seabed at a rate of about 15 centimetres per day.
If conditions are right, the scales remain lying and are eventually buried in their billions of billions.
Estimates indicate that coccolithophores globally produce more than 1.5 million tonnes of calcium carbonate per annum – equal to the weight of the Gullfaks C platform, which ranks as the heaviest structure ever moved by humans.
Three things must be in place for an oil and/or gas field to form – a source rock, a reservoir rock and a cap rock which prevents the petroleum from escaping.
In the case of Ekofisk, we know quite a bit about how these three components originated.
Source rock – Draupne
The Ekofisk source rock dates from the Jurassic period, 161-145 million years ago, and comprises organically rich black shales known as the Draupne formation.
In Norse mythology, Draupne was the gold ring worn by the god Odin which formed another seven rings every ninth day – in other words, an endless source of prosperity.
So the name is appropriate for a formation found over most of the Norwegian continental shelf (NCS), which has put huge volumes of petroleum into most of Norway’s fields – including Ekofisk.
Cretaceous reservoir rock – Tor formation
The Cretaceous period followed the Jurassic and lasted for 145-66 million years, with the last 10 million of these forming the Campanian and Maastrichtian stages.
Conditions then were favourable for coccolithophores over much of the southern and central North Sea as well as England, Denmark and France.
Countless coccoliths were deposited on the seabed. Since the latter was neither flat nor stable, they were moved around by small slips, landslides and/or mud flows which could be activated by earthquakes, before being finally buried by their successors.
The Cretaceous ended in a mass extinction event, when up to 70 per cent of all life on Earth vanished – including the dinosaurs.
This wipe-out was unleashed by a massive asteroid strike in what is now the Gulf of Mexico, where the Chicxulub crater is about 150 kilometres in diameter and 20 kilometres deep. The asteroid itself may have measured 80 kilometres.
Palaeocene reservoir rock – Ekofisk formation
That impact nevertheless failed to destroy all marine life, and the “sea scurf” continued to rain down in the following Palaeocene period.
During its first million years, known as the Danian stage, further tens of metres of calcium carbonate were deposited. But changed seabed conditions and a colder climate had an impact.
The amount of reworking which the material experienced varied and decreased, while the content of silica derived from microscopic diatoms and radiolarians increased.
Lower sea levels also meant an increased influx of sediments from land (terrigenous material) in the chalky plates heaping up on the seabed.
Porosity and permeability
These sediments usually have up to 50 per cent porosity (cavities) when deposited. But this will be considerably reduced by burial and diagenesis (the physical, chemical and biological changes which occur during conversion from sediment to stone).
In some case, that reduction can be down to well below 10 per cent. However, the good conditions around the Greater Ekofisk Area (GEA) meant that much of the porosity in the chalk was retained.
It has been calculated at 25-40 per cent. By comparison, a good sandstone reservoir – which is the kind usually found on the NCS – has a porosity of 30 per cent.
Permeability is also needed to get much oil out of a rock, and the “primary permeability” of Ekofisk chalk is low since the connections between its pores is poor/constricted.
But the field has enjoyed another stroke of luck here. A large number of fractures in the reservoir have improved its permeability and provide good production properties – at least initially. See water injection.
Cap rock and trap formation
After the deposition of the Ekofisk formation, conditions changed so that the overlying sediments lost all their porosity when buried and became tight (impermeable).
That allows them to function as a cap rock which seals the reservoir formed by the Tor and Ekofisk formations.
The fractures mentioned above were created at the same time as the rocks were subject to movement when large quantities of underlying salt shifted. This also produced large domes and therebycreatedtrap structures where oil and gas can accumulate.
In other words, the oil migrating from the source rocks has gathered in the reservoir formations under the cap rock – and in amounts which can be difficult to imagine.
The Ekofisk reservoir is as thick as the Eiffel tower is tall and covers an area of 40 square kilometres – the same size as 5 500 football pitches.
Recoverable oil in Ekofisk totals 3.5 billion barrels, which would be sufficient to supply the whole world with crude for 35 days.
Roughly 1.1 billion standard cubic metres (scm) of oil (about 6.9 million barrels) and 300 billion scm of gas were present in Ekofisk when production began.
That corresponds to twice Norway’s annual water production. It also represents more than 100 times annual Norwegian energy consumption and just over 100 days of global oil usage.
It is impossible to get all the oil out of a reservoir, and a distinction is therefore drawn between reserves in place and recoverable reserves.
However it is measured, though, Ekofisk ranks as one of the very largest fields on the NCS. The original estimate for petroleum recovery from the field was 17 per cent. It is now expected to exceed 50 per cent – in part through waterflooding.
Halbout,Michel T, Giant Oil and Gas Fields of the Decade: 1968–1978. AAPG Memoir 30, 1980.
Ivar B. Ramberg – Inge Bryhni – ArvidNøttvedt – Kristin Rangnes (ed.’s), The Making of a Land, NGF 2008
Published 23. September 2019 • Updated 9. June 2023