The Europa Chemical Injection (CI) umbilical was installed at the Mars platform in 1999. Over the past 16 years, many of the umbilical tubes were taken out-of-service due to leaks in the topside termination assembly. The umbilical was reterminated from the Mars platform during July and August of 2015. As a result, 6 out-of-service tubes were restored and the life and functionality of the umbilical was extended. In addition to the operational gains, the effort provided significant savings by mitigating the need for a replacement umbilical and simplifying a future abandonment operation. This is believed to be the industry's first ever topside retermination of an in service, steel tube umbilical.
The success of this offshore operation is significant to Shell and the greater operations community due to anticipated maintenance of aging, steel tube umbilicals like the Europa umbilical. Shell has several other umbilicals which were manufactured and installed in this same time period which may benefit learnings from this activity. It is believed based on engagement with the Europa operating partners that the learnings from this operation may also benefit other deepwater operators.
This first-of-its-kind operation established a best practice procedure to conduct a retermination of an aging umbilical from the platform. A new friction/squeeze clamp design was developed and qualified to 3 times the design load. The allowable squeeze limit of the umbilical was well above the calculated and recommended values. A unique chemical displacement strategy was utilized to partially displace the umbilical to accommodate cutting and welding activities. This strategy utilized S-traps along the umbilical route to prevent chemical backflow which drastically reduced the displaced volume of chemical.
In the current economic climate, operators are looking for ways to prolong the life of their aging assets. This operation is an example of a unique, cost-effective solution to maturing brownfield assets.