Powering up to meet market demand

April 8, 2010

With the offshore umbilicals market emerging from its recent slumbers and power cable demand from both the oil & gas and wind energy sectors picking up strongly, further expansion of Nexans’ Halden facility in Norway could well follow the current extension and makeover of the company’s flagship Skagerrak. Meg Chesshyre reports.

For many years Nexans’ Halden plant has specialised in the manufacture of high-voltage submarine power cables as well as interplatform cables and umbilicals for the offshore industry, with the company’s other Norwegian factory, Rognan, supplying submarine fibre optic cables and electrical elements, and fibre optics for umbilicals.

Nexans secured a frame agreement with BP Exploration & Production last summer for deepwater umbilical projects in the Gulf of Mexico that could be worth as much as $300 million in total.


Ragnvald Graff, Nexans’ marketing and sales director for the energy division, comments: ‘Before the previous frame agreement was signed with BP in 2002 they came to us and said they had many problems with the electrical systems with their subsea equipment, so they wanted this frame agreement to solve these problems. I believe we have. I think the track record from our deliveries under the frame agreement has been zero failure after the product has been taken into use. I believe they came to us because we are the only umbilical manufacturer that has everything in-house, electrical and fibre optic elements, power cores, welding of steel tubes etc.’

The BP agreement covers the design, manufacture and supply of bespoke umbilicals that will carry fluid, power, control and telecommunications services for new subsea oil and gas projects or replacements in water depths up to 2000m. During the term of the agreement, Nexans could deliver more than 200km of umbilical products to BP. The umbilicals for the Gulf of Mexico will be designed and manufactured at Halden. The first two projects under the agreement, Na Kika and Mad Dog, are due for delivery late summer.


This new frame agreement follows the success of the previous umbilical frame agreement between BP and Nexans for the Gulf of Mexico, which ran 2002-08. During this time, Nexans delivered several umbilical projects for BP worth a total of $130 million. Nexans designed and manufactured the world’s first subsea service umbilical to integrate a high voltage cable for BP America in 2005/6. The 26km power-umbilical was installed in the Gulf of Mexico as part of a project to retrofit two existing subsea wells in BP’s King complex with multiphase pumps (OE July 2007).

According to Graff, integration of the power cable and umbilical functions in a single unit enables a HV (24kV) supply to be provided in deep waters, which has not previously been possible. The concept of integrating HV electrical power cables in a subsea umbilical is very challenging from both the mechanical and electrical design aspects, with electrical interference between conductors and inductive losses in the steel tubes of particular concern.

An additional challenge is the water depth. Nexans designed a software package in-house, Uflex (umbilical flexing), for the accurate prediction of the behaviour of complex umbilicals, which is being used increasingly within the industry. Power umbilicals mean cheaper platforms, explains Graff, as the requirement for heavy equipment is taken off the platform and placed on the seabed. He adds that Nexans is carrying out studies for umbilicals down to 3000m, and looking at the effect on copper at those depths. Na Kika is already at 2300m. The company has a large engineering group in-house looking at both umbilicals and power cables.

Nexans is currently carrying out a €33.5 million fast track contract for Petrobras to develop, manufacture and supply the electrohydraulic control umbilicals for the Tambau and Urugua deepwater natural gas and oil fields, in the Santos Basin around 130 miles offshore Rio de Janeiro. The umbilicals will connect the FPSO Cidade de Santos MV20 to the subsea manifolds and then connect the manifolds to the production wells.

The Halden facility is producing over 65km of umbilicals, in 16 lengths, to be installed in water depths reaching 1500m. The umbilicals will be exceptionally heavy, weighing 2400t. The accessories are supplied locally in Brazil, then shipped to Halden for assembly on to the umbilicals. Delivery is expected to be completed by late summer. Nexans has had a technical co-operation with Petrobras for over eight years, and introduced the steel tube umbilical on the Roncador project.

Nexans also has a €42 million order from Saipem subsidiary EMC to develop, manufacture and supply umbilicals and associated equipment for the subsea development of the Total-operated Usan deepwater oilfield in Nigeria. Delivery is expected in 2011.

Graff admits that the umbilical business has not been so good the last 12 months. ‘But we see some improvements now’, he adds. ‘We have quite a few larger projects of over 100km on tender at the moment.’ He rates the North Sea, the Gulf of Mexico, Brazil, West Africa, and the Far East, with large projects emerging offshore Australia and China, as the most important markets for umbilicals.

Skarv direct heating
The Halden plant is carrying out a €11 million contract for BP Norge to supply a direct electrical heating (DEH) system for the Skarv field subsea production pipeline in the Norwegian Sea. Nexans lays claim to being the only supplier with experience of this highly specialised technology and has already supplied this type of system for 17 subsea pipeline installations.

A 12in diameter production pipeline will be installed from one of the production wells at the field to the FPSO vessel at Skarv. The distance between the well and vessel is about 13km. Nexans is supplying all the cables and dedicated subsea equipment for the DEH system to be delivered for installation this spring. At low production and shutdown scenarios, a DEH-system will be used thus preventing blockage of the pipe. For Shell/Statoil on Ormen Lange, Nexans has designed a DEH system for the most critical area of the pipeline, which can be activated when necessary. It has not yet been needed.

The DEH system was developed through a partnership of Norwegian operators and suppliers, and Graff points out that Nexans is the only supplier so far to have delivered these systems. Statoil is a major user of this technology and the Åsgard, Huldra, Kristin, Norne, Tyrihans, Alve and Morvin fields all now have Nexans DEH systems installed. A number of methods may be used for maintaining flow, such as chemical injection, but the company says DEH has proved to be a reliable, ecofriendly and cost effective solution to the problem.

Offshore wind success
On the offshore wind side the most recent success has been a contract worth around €100 million from a consortium of Dong Energy, E.ON and Masdar to design, manufacture and supply the high voltage subsea power export cables that will connect the London Array wind farm in the Thames Estuary to the UK grid.

Construction of the wind farm is taking place in two phases: the first 630MW phase, consisting of 175 turbines, is expected to be completed and generating in 2012; the future second phase will bring total capacity to 1000MW. The power export cable contract comprises the design, manufacture and supply of four 150kV XLPE (crosslinked polyethylene insulated) submarine power cables to be laid in parallel, each 53-54km in length. Halden will deliver two of the cables in 2011, and two in 2012, all in single continuous lengths and incorporating fibre optic elements manufactured at Rognan. The contract also includes the cable accessories such as repair joints and terminations.

Nexans also has a €50 million contract from Centrica to design, manufacture and supply the high voltage subsea power export cables for the UK Round 2 Lincs wind farm being constructed 8km off the English Lincolnshire coast. The Lincs power export cable contract comprises the design, manufacture and supply of two 145kV XLPE subsea power cables to be laid in parallel, each 50km in length, that will connect the wind farm to the existing UK national grid substation at Walpole, North Norfolk. The cables will be delivered during 2011.

Also offshore the UK, Nexans has two contracts from Statoil for the Sheringham Shoal wind farm 20km off the Norfolk coast. The first, with an estimated value of €24 million, is to supply the submarine export cables. The contract scope includes engineering, procurement and construction of two 22km145kV XLPE submarine export cables, and a spare cable with associated equipment. The export cables are due for delivery this month. The second contract, worth around €12 million, is for the supply of 81km of infield cables and equipment. The infield cable contract comprises the design, manufacture and supply of 81km of 36kV XLPE submarine power cable. They are due for delivery in June.

Offshore Belgium, Nexans has won a contract worth around €39 million to supply the subsea power export cables for phase one of the Belwind wind farm, on the Bligh Bank. At 46km off the coast of Zeebrugge, Belwind is the furthest offshore of any European wind energy development to date.


Nexans will supply and install 52km of 170kV high voltage power export cable with an optical fibre insert to Dutch contractor Van Oord Dredging & Marine Contractors, the EPC contractor for the project’s first phase. Delivery is due this summer and the cable will be buried using Nexans’ Capjet trenching system onboard the newly extended Nexans Skagerrak. Belwind is scheduled to come onstream in 2011.

The UK is number one in the wind farm market in terms of megawatts installed, under construction, and future plans, while Germany has major potential, according to Olivier Angoulevant, export sales manager, high voltage cables, in Nexans’ energy division. ‘As well as prospects throughout Europe, especially the North Sea countries, there are also projects emerging in Asia and America,’ says Angoulevant. He believes Nexans is well positioned for the future with the projects that it has completed and those currently under way.

If the order book holds up, Nexans has plans to expand the Halden factory including doubling the capacity of the 100m extrusion tower. The tower, built in 1994, has been designed for two extrusion lines but only has one at the moment. This expansion would probably necessitate other modifications such as increased storage. Graff stresses that any expansion will be project triggered.

The Norwegian operation also runs the production joint venture NVC, in Japan, owned 66% by Nexans and 34% by Viscas (a joint venture between Furukawa Electric Co and Fujikura). The Futtsu facility was opened in late 2006. Work has included a large cable from Hainan island to mainland China. OE

MORE OF SKAGERRAK: Nexans is extending its offshore cable-laying workhorse by 10m to give the vessel more stability with larger loads. Capable of carrying 7000t of cable, Skagerrak has been around since the early 1970s and was hailed at the time as the offshore industry’s first purpose-built cable layer. The vessel derived its name from its early work laying cables across the Skagerrak –the stretch of ocean between Norway and Denmark.

As well as adding a new mid-section, UK shipyard Cammell Laird is carrying out a life extension programme on Skagerrak in readiness for her next assignment at BP Valhall, due to start this month, followed by the Belwind export cable job in the summer – and all other installation jobs thereafter.



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