Building it on a big scale

28.06.2017
Work on the first development phase for the Johan Sverdrup field involves no less than 14 000 people at 20 different places around the world. Norwegian Continental Shelf has visited a couple of these sites.

| Rune Solheim (text and photos)

Drone-eye view. The quarters platform for Johan Sverdrup is under construction here at Kværner Stord. While the biggest structures are inside the workshop on the left, the three covered modules in the foreground are also for this field. On the right, the Statoil-operated Njord platform is in for maintenance.

Drone-eye view.
The quarters platform for Johan Sverdrup is under construction here at Kværner Stord. While the biggest structures are inside the workshop on the left, the three covered modules in the foreground are also for this field. On the right, the Statoil-operated Njord platform is in for maintenance.

 

A huge blue crane capable of lifting more than 1 000 tonnes forms the gateway to Kværner’s yard at Stord south of Bergen. Immediately behind it towers the grey floater carrying the Njord platform topside, which has been towed in for upgrading.

Located centrally on the site, the workshop itself is currently fabricating and outfitting the bottom deck for the Johan Sverdrup quarters facility.

The whole shop is mounted on wheels and can moved aside as the structure grows. Other modules for the platform’s topside stand just outside it.

 

Outfitting. The topsides for the Johan Sverdrup quarters platform is starting to look like an offshore installation.

Outfitting.
The topsides for the Johan Sverdrup quarters platform is starting to look like an offshore installation.

 

Giants

Much offshore history has been made at this yard, including work with a number of the giant structures on the NCS such as Statfjord A, Gullfaks A, B and C, Oseberg A and Troll A.

Also on the reference list are Snorre A and B, the Njord and Kristin facilities, and the Norne and Åsgard A production and storage ships.

But today’s focus is on Johan Sverdrup, the field which has boosted optimism on the NCS. Kværner and US engineer KBR are building a topside with a ninestorey accommodation block.

This platform will also house the nerve centre for the whole field – the control room – and provide space for three helicopters on top.

One of these will be in a hangar on stand-by for search and rescue missions across the whole Utsira High area. And nine lifeboats will be available for the four fieldcentre platforms.

 

Forklift Yard worker Borowski Bartlomiej operates a forklift as he helps to build Johan Sverdrup at Kværner Stord.

Forklift Yard worker Borowski Bartlomiej operates a forklift as he helps to build Johan Sverdrup at Kværner Stord.

 

Activity

Johan Sverdrup is generating a high level of activity at Stord. The topside being built there will include the world’s largest offshore accommodation unit to date.

With 560 berths, gym, cinema and sick bay, this “marine hotel” incorporates a set of modules being outfitted only a few crane lengths away at sub-contractor Apply Leirvik.

Moreover, the support module for the drilling platform is taking shape at Aibel’s yard in Haugesund about 60 kilometres further south.

Kværner’s Verdal yard in mid-Norway has the job of building the three largest of the four steel platform jackets under an engineering, procurement and construction (EPC) contract.

The heaviest and most complicated jacket, intended to support the riser platform, is approaching completion and will be delivered this summer.

Design work for the drilling and process platform jackets was completed in the late autumn of 2016. Prefabrication and assembly of these are well under way at Verdal for delivery next year.

 

Local spinoffs. “Building Johan Sverdrup has benefitted not only Kværner but also the whole Stord community,” says Edmund Skålnes, construction manager at Kværner Stord.

Local spinoffs.
“Building Johan Sverdrup has benefitted not only Kværner but also the whole Stord community,” says Edmund Skålnes, construction manager at Kværner Stord.

 

Proud

Construction manager Edmund Skålnes at Kværner Stord is pleased and proud that the yard proved sufficiently competitive to win fabrication contracts this big in an ever-tougher world market.

The job is worth NOK 6.7 billion to the Norwegian group. Its efforts to boost productivity and cut costs, combined with solid expertise and ability to deliver, help to explain why it won.

“We were facing a period of reduced activity when the Johan Sverdrup order was placed,” says Skålnes. “That benefited not only us, but the whole Stord community.”

The construction process has so far gone smoothly, reports Trond Ove Lerøy, who is the client’s on-site supervisor.

“It’s a great strength that wellknown and tested components and building methods are being used. That both simplifies the work and makes it more secure.”

 

Team. Construction manager Edmund Skålnes (right) at Kværner and Statoil’s site supervisor Trond Ove Lerøy are collaborating over the process of completing the Johan Sverdrup quarters platform.

Team.
Construction manager Edmund Skålnes (right) at Kværner and Statoil’s site supervisor Trond Ove Lerøy are collaborating over the process of completing the Johan Sverdrup quarters platform.

 

No headaches

New technology often gives rise to headaches, cost overruns and delays for field developments. But that is not the case with Johan Sverdrup.

The challenge here is not the known technology, but the scale of the project and the many elements being built separately which need to come together at the right time.

“Fortunately, we’re well on schedule and haven’t had any serious incidents,” says Skålnes. “Much of the necessary hardware was ordered even before we landed the contract. Along with good engineering work, that’s given us positive start.”

Specifications and drawings are closely followed up, Lerøy explains. “Checking that everything’s been done correctly is a huge job.

“We have 70 000 sheets which have to be checked against the tag number for each component. It’s also very important that things arrive at the right time and place.”

Skålnes adds that changes are not welcome. “These usually mean that we must take a step back and amend both plans and methods, which presents extra challenges for fabrication.”

 

Stories

A few kilometres away, Apply Leirvik is building six of 11 components for the accommodation block, covering seven of its nine stories. The other two are coming from Kværner.

Construction began in April 2016, but preparations for tackling the Johan Sverdrup job were initiated as early as 2012. Hook-up and outfitting of Apply Leirvik’s modules started in May, with delivery due to Kværner in October 2018.

The company has long experience of building offshore quarters modules, extending from the Statfjord field in 1976 to the Gina Krog development last year.

Operator Statoil produced a rough design outline and then left it up to Apply Leirvik to fill in the details. It is providing engineering services as well as building the modules.

The last two of the latter structures are being constructed by Apply Emtunga, the fabricator’s Swedish subsidiary in Gothenburg.

 

Multidimensional. Hege Robberstad is a 3D modeller, creating detailed visualisations of the quarters platform at contractor Apply Leirvik.

Multidimensional.
Hege Robberstad is a 3D modeller, creating detailed visualisations of the quarters platform at contractor Apply Leirvik.

 

Control

“We’ve developed our own milestone system, a project management model, to maintain detailed control of both engineering and fabrication from start to finish,” says Øystein Kvalvik.

Engineering leader for the accommodation modules at Apply Leirvik, he reports that 4 070 design documents and drawings for building and documentation have been produced.

Design coordinator Odd Peter Ørjasæter calls up detailed threedimensional drawings of the quarters platform on a big screen.

He explains that specific requirements are set for hygiene, ergonomics, lighting and noise where people will be present on the platform, in addition to all the technical specifications.

The 11 modules are designed to be hooked up very quickly. They add up to 14 500 square metres of accommodation – the rough equivalent of two football pitches.

 

Systematic. Apply Leirvik has developed a special system to manage the accommodation block, report engineering leader Øystein Kvalvik (left) and design coordinator Odd Peter Ørjasæter.

Systematic.
Apply Leirvik has developed a special system to manage the accommodation block, report engineering leader Øystein Kvalvik (left) and design coordinator Odd Peter Ørjasæter.

 

Reversible

The quarters platform will have 450 cabins, and 110 of these are fitted with a reversible bed. That allows shift workers to share a cabin while retaining their own personal berth.

Each cabin measures 7.6 square metres, with the bed placed crosswise to give more sense of space. All these units are delivered readybuilt from Finland for immediate assembly.

Account has been taken of possible requirements for additional accommodation capacity, with mooring locations for three flotels provided on the field.

The need to house as many as 560 people on the platform will only arise occasionally, during maintenance turnarounds and modification work. Normal field staffing will be about 220 people.

Although the steel jacket might look a little flimsy in relation to the massive structure it has to support, all the weight calculations are in order.

The accommodation module is being constructed with the two lowest stories in steel and the rest in aluminium, which provides a weight saving of 1 000 tonnes.

If the cranes and helideck are ignored, this offshore hotel looks a bit like the superstructure of a cruise ship – with shiny aluminium surfaces pierced by rows of cabin windows.

It then remains to be seen whether the rest of the voyage will continue calmly towards the planned start of production in 2019.

 

Keeping it all together

 

Construction work for Johan Sverdrup, the new giant North Sea field, is ahead of schedule at the midpoint and could be NOK 26-27 billion cheaper than planned. Making sure things stay that way could be a challenge.

| Rune Solheim (text and photo)

3D model. The various modules forming the quarters platform topside. (Illustration: Apply Leirvik)

3D model.
The various modules forming the quarters platform topside.
(Illustration: Apply Leirvik)

 

Halfway is a milestone,” accepts Trond Stokka Meling, Statoil’s technical head for this phase-one project. “We’re entitled to acknowledge it, but not to celebrate.

“Everyone knows that the challenges could well arise in the second half. We can celebrate when everything’s finally put in place.”

Although the field is being developed with known technology, some things have not been done before. That includes the first use of Pioneering Spirit – the world’s largest heavy-lift vessel – for offshore installation.

This ship is due to install the topsides on three of the four platforms under construction, although its experience in this area is limited to removing such structures on Yme and Brent D.

“We’ve made pretty formidable technological preparations to ensure that this will go well,” says Meling. “We also have a whole month’s weather window in summer – far more than the job needs.”

 

Platforms

The field installations will comprise four platforms, for drilling, risers, processing and quarters respectively.

Three large modules are due to be hooked up on the drilling platform topside during September, while others will be delivered by Aibel’s yard in Thailand.

With a drilling rig from the Nymo yard in Grimstad and the drilling support module from Aibel’s Haugesund yard, this platform is scheduled for towout to the field in the summer of 2018.

The riser and process platforms are under construction at the Samsung yard in South Korea and set to sail for Norway next year and in 2019 respectively.

 

Phase one. The chosen solution for the first development phase is a field centre with four specialised platforms for quarters, process, drilling and risers respectively. They will be linked by bridges. (Artist’s impression: Statoil)

Phase one.
The chosen solution for the first development phase is a field centre with four specialised platforms for quarters, process, drilling and risers respectively. They will be linked by bridges.
(Artist’s impression: Statoil)

 

Power

A high-voltage direct current connection (HVDC) facility supplied by South Korea will be installed on the riser platform as part of delivering power from shore to the facilities.

Preparations for the transformer station at Haugsneset, just to the east of the Kårstø terminal north of Stavanger, are well under way.

This installation will convert alternating to direct current, with the HVDC turning it back to alternating on arrival – a process which minimises power losses in transmission from land.

The process generates a good deal of heat and radiation and therefore takes up a certain amount of space. Johan Sverdrup is to receive 100 megawatts from shore.

 

Control

The offshore control room will run all four field-centre platforms (set to rise to five in the second phase). These facilities will have a combined staffing of about 280 people.

In addition, the control room will manage the subsea systems, a possible unstaffed wellhead installation, and the power supply facility on land at Haugsneset.

Part of an organisation of about 130 people linked to the field centre, the onshore operations centre will deploy real-time data and expert tools for support and decision-making.

Taking power from shore eliminates the need for big diesel or gas-turbine generating sets on board. But boilers needed by the process plant usually run on waste heat from the generators.

In the first stage, this heat will be provided by gas, with power from shore taking over in the second phase. The quarters platform will also carry a diesel-driven emergency generator.

 

Not at any cost. “We’ve achieved fairly dramatic cost cuts,” affirms Trond Stokka Meling, technical head of the Johan Sverdrup development. “A discussion has been under way in the Norwegian press on whether we’re putting too much pressure on the suppliers. But we’re not interested in bankrupting them or undermining safety.” (Photo: Statoil)

Not at any cost.
“We’ve achieved fairly dramatic cost cuts,” affirms Trond Stokka Meling, technical head of the Johan Sverdrup development. “A discussion has been under way in the Norwegian press on whether we’re putting too much pressure on the suppliers. But we’re not interested in bankrupting them or undermining safety.”
(Photo: Statoil)

 

Size

The challenge for the project is its size. Everything must fit together even though construction has been pursued at 20 sites around the world.

Meling underlines the importance of information being conveyed in a precise manner and interpreted in the correct way.

“All the equipment must work when it comes offshore. Interfaces, design and construction have to be done well. The preconditions must be the same at all the yards.”

He recently visited a supplier in Poland providing seven cranes. Follow-up is important to ensure that they work properly offshore. Correcting anything out at sea is more expensive.

A challenge arose after a bridge across an Italian motorway collapsed. Driving heavy vehicles over such structures was banned for a while in northern Italy, making it impossible to get equipment to the docks for shipping out.

“We were locked in,” says Meling. “Fortunately, we found roads which could be used and sent the freight by river barge to the coast and onto the cargo ship.”

 

Share

Asked how much of the Johan Sverdrup development is being constructed in Norway, he says it depends on how the domestic share is calculated.

About 70 per cent of the contracts have gone to companies with a Norwegian address. However, some of these are allocating part of the work to their foreign branches.

An example is drilling platform contractor Aibel. It has an office in Oslo and a yard in Haugesund, but is using its Thai facility for some work because of a lack of capacity in Norway.

Palfinger provides another case in point, with an office in Bergen while manufacturing its cranes in Poland. So the picture is nuanced, Meling points out.

“The suppliers have looked at how they can be competitive in an international market. They can often compete on engineering and hook-up, but need to weld steel in other countries.

“When the company is Norwegian, we communicate with its management here. That’s clearly an advantage. In technical terms, however, we’ve no grounds for saying that Norway does things better than elsewhere as long as the specifications are met.”

 

Construcion

Around 14 000 people will be employed on the Johan Sverdrup project at peak, and the whole construction period involves 51 000 work years. But Meling is unsure how many of these are Norwegian.

A decision is due this summer on permanent monitoring of the Johan Sverdrup reservoir with the aid of four-dimensional seismic surveying.

This involves repeating threedimensional surveys at regular intervals to check developments in the formations once production is under way.

While the cost of such surveillance has been included in the field’s plan for development and operation (PDO), it must be approved by the partners before 1 July.

Meling notes that opportunities to acquire sub-surface data on an annual basis will provide increased understanding of reservoir behaviour during production and water injection.

“That in turn allows us to improve the planning of new wells and methods for boosting resource recovery. Our ambition is to get out 70 per cent of the proven hydrocarbons.”

Operator Statoil and its partners have a 50-year production time frame, and need robust data to reduce uncertainty. That can improve the recovery factor and extend the field’s commercial life.

 

Fantastic

Meling describes the economics of Johan Sverdrup as fantastic. “When sanctioning phase one, the bill was put at NOK 123 billion. We’re now down to NOK 97 billion.

“We’ve achieved fairly dramatic cost cuts, and a discussion has been under way in the Norwegian press on whether we’re putting too much pressure on the suppliers.

“But we’re not interested in bankrupting them or undermining safety. We take great heed of health, safety and the environment. A project isn’t a success if we suffer a serious incident.

“Our positive experience is that we’re getting what we ordered, to the right quality and by and large on schedule, so that we don’t have to spend heavily on repeating the work.”