Unbilical stability assessment

The problem

As part of a major project in the Middle East, two subsea umbilicals were installed on offshore platforms in October 2006. Anchor blocks that were manufactured to limit movement of the unstable sections of the umbilicals on the seabed were not installed. In addition, 3rd party incidents had caused damage to the umbilical.

The solution

Jee had been monitoring the situation since installation and carried out stability assessments, creating Orcaflex models of the umbilicals at high risk areas.
Jee carried out an assessment of stabilisation methods and made recommendations on the most suitable.
In addition, Jee carried out span assessments and calculated mattress spacings to determine the optimum required spacing for stabilisation and protection.
The umbilicals were resurveyed in 2008 and Jee has subsequently updated assessments in light of the new survey data.

The benefits

Jee undertook verification of many elements of the pipeline and umbilical design and has provided ongoing support to the operator with respect to engineering and installation issues.
Jee has extensive experience of stability analysis, installation methods, pipeline and umbilical protection and risk assessment.
Jee provided cost effectiveness for the client, by determining the optimum practical stabilisation solution for the umbilicals in terms of performance, cost and schedule to meet the environmental and service conditions and ensure on-bottom stability of the umbilicals.