The umbilical technology is now extended to include large bore flowline/ riser and HV- power cables in deep water. Extensive development programs including advanced design verification tools, that gives high confidence in the new generation of deep water umbilical products. The development of the IPU solutions started back in 1998 are now completed and numerous field applications have been studied. To enable application of the IPU technology to any scenario, the USAP has been developed and applied with success and high accuracy. The USAP computer program analyzing stress of separate helix elements wound around a central core and exposed to tension, pressure, temperature, friction or residual strain during reeling, installation or operation. The use of more advanced tools improves the confidence and understanding of the products and will reduce the requirements for testing in the future. Trough the work performed on Gas Lift Risers, Integrated Production Umbilical (IPUÖ) and other deepwater umbilicals we have increased the knowledge in designing more complex umbilicals.

The paper will also present the design tools used in the engineering, fabrication, installation and operational testing.


Based on the knowledge and experience acquired during several years of development work, the feasibility of using more complex umbilical and flowline technology is now possible. Use of alternative technologies for the future exploitation of the hydrocarbon resources will offer a great number of advantage.

The main performance requirements of such solutions are addressed with respect to flow assurance, electrical design and structural behaviour.

Within one single system the following can be included:

  • thermal insulation

  • electrical heating

  • HV- power cables 400mm2for gas separation subsea

  • Thermal monitoring

  • Stress releaving members to enable deep water installation of electrical conductors.

  • Large bore tubes and pipes from 4-10"

  • All control umbilical functions

Figure 1: Typical IPU design (Available in full paper)

In the last 5 yers significant amount of development work are done to develop design tools that can be used to determine the global and local stress and strain within the more complex structures.

The aim of this paper is to show:

  • Examples of design tools and how these design tools can be used.

  • Testing done to verify that the analysis tools give good correlation to the test results, regards local and global structural behaviour, thermal insulation and electrical design.

  • The IPU technical status and describe the manufacturing process.

  • The qualification methology and the test metodes used to demonstrate that the technology gaps are closed in accordance with the requirements of the DNV Recommended Practice RP-A203 Qualification Procedures for New Technology

USAP Analysis Features

The computer program USAP has been developed in order to enable evaluation of the stresses and forces hat occur during installation and operation of umbilicals and IPUÆs. It focus on the effects that are of special importance for deep water concepts and can be used to determine both global and local behaviour including loads that distribute stress and strain away from the location were the load was applied.

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