Umbilical Systems

Nexans Norway has cable design and manufacturing traditions reaching as far back as 1915. This vast experience lies behind the development of Nexans' cable- and umbilical technology.

Nexans is a world leader in the manufacturing of subsea umbilical systems. Nexans provides umbilical systems from design, engineering, and manufacturing, through testing, installation and commissioning.

Nexans manufacturing capabilities have traditionally been oriented towards very long, intercontinental submarine power cables. This means that Nexans' manufacturing equipment can handle long umbilical lengths and large weights and volumes - all traits of a subsea to shore umbilical, the latest trend in the offshore industry. Nexans has already supplied umbilicals with a continuous length of more than 100 km, and will have supplied the 143 km continuous length umbilical to Statoil's Snøhvit (Snow White) project in 2005. Other historic key numbers include a total delivery weight of 4000 tons, a max. unit weight of 135 kg/m, and an outer diameter of 213 mm.

Nexans umbilicals are used in all types of applications; connecting subsea installations; subsea installations and fixed- and floating platforms (semis) and FPSOs; as well as subsea to shore systems. Nexans' umbilicals are used world-wide, from both the Norwegian and UK sectors of the North Sea, to the Gulf of Mexico, offshore Brazil, offshore North- and West Africa, as well as in the Far East.

Nexans Norway has in-house capabilities in all aspects related to umbilical system design. Our competent staff covers all aspects of an umbilical project, and key personnel follow the process from the bid phase, through engineering, manufacturing, testing and installation.

There are two continuing trends in the offshore umbilical industry:
1. Oil production in deeper and deeper waters
2. The desire to perform subsea processing

Both these trends affect the umbilical design:
1. The weaker cross-section components must be able to withstand the larger forces and elongations
2. The cross-section must include high voltage power elements

Nexans Norway is well positioned to meet these challenges for three reasons:
1. Nexans has in-house design capabilities and manufacture their own electrical and fiber optic elements
2. Nexans has in-house design capabilities and manufacture their own power elements and power cables
3. Nexans has in-house design capabilities giving their engineers a profound understanding of how cross-section forces translate into stresses and fatigue through their UFLEX software.

Offshore oil and gas production continues to move into deeper and deeper waters. This puts higher and higher demands on the umbilical systems to ensure operational integrity throughout the lifetime of the fields. In order to handle this risk increase, Nexans' engineering experts need to have a profound understanding of the issues that govern the umbilical and accessories design.

Nexans has a strategic goal of being technology-driven. One outcome of this is the UFLEX software - a state of the art FE-based, non-linear calculation program for stress analysis of complex umbilical cross-sections. Extensively validated through full-scale tests. The UFLEX tool is an invaluable tool for ultra deepwater umbilical engineering. Together with our full-scale dynamic flex test facility, Nexans has in-house capabilities to validate the advanced tools and sophisticated design methodologies.

Nexans has delivered dynamic and static umbilicals to several deepwater projects all over the world:

• Shell Nakika E/H Umbilical, 2300 m water depth
• Petrobras Roncador E/H Umbilical, 2000 m water depth
• BP Thunder Horse E/H Umbilical, 1890 m water depth
• BP Atlantis E/H Umbilical, 2150 m water depth
• ExxonMobil Erha E/H Umbilical, 1200 m water depth
• BP King E/H Power Umbilical, 1500 m water depth

Umbilical Accessories
Umbilical accessories form part of an umbilical system supply and comprise platform hang-off systems, dynamic and static bend stiffeners and -restrictors, J-tube or I-tube centralizers or seals, and protection, repair splices, subsea terminations and buoyancy elements. Nexans subsea terminations include field proven pressure compensated electric and fiber optic splice boxes that have an excellent track record. The terminations have been pressure-tested for 3000 meter service.