Offshore Composol Vessel

Sharjah Floating Oil Storage Unit Vessel Repair

An offshore oilfield operator in Sharjah were interested in finding a permanent solution for a corroded deck plate areas on their “FSU”-Floating Oil Storage Unit main top deck. The FSU is a 250,000 ton converted tanker which has been specially converted to store the field oil production and the corroded deck area in question was the top part of the storage tank.

Traditional methods of welding steel plates onto the affected area had been considered, however, there were two distinct disadvantages. Firstly, an additional weight problem from the 15mm thick plates required, would have added significant loads onto the existing substructure. Secondly, the preparation for cutting and welding additional re-enforcement plates, would have necessitated that all the affected storage tanks be drained, gas freed, then purged, a time consuming and costly procedure. Traditional methods would have also reduced storage capacity and have inhibited field production during the repair duration.

The operator contacted IMG Composites who carried out an initial site survey and then designed a repair which would be lightweight and could be applied without emptying the storage tanks. The ability of the composite reinforcement to move and flex with the tanker deck and the structural strength provided by such a repair method was also a crucial factor in operator’s decision.

The major advantage to the operator is that these repairs can be undertaken whilst the system or pressure containment vessel is still ‘live’. Using traditional methods the operator would have to decant product from the vessel, prior to gas freeing and then purging out all before welding on re-enforcement plates internally or externally.
Using this new IMG Composite Repair procedure, there is minimal disruption as there is no hot-work involved. Once completed, the reinforced area can be painted over to blend back into the rest of the paint system used.

A 25 square metre top plate deck area was reinforced and took 4 days to install without any disruption to operations.

The operator commented that: “The repair method selected proved to be innovative, and has enabled us to continue normal un-interrupted operations without impacting safety, production or the total storage capacity.

The final composite repair has also proven to be simple, strong, and durable, and will provide a permanent solution to an otherwise difficult and complex problem, when compared to repair using traditional methods. Traditional methods would have undoubtedly have been more expensive, time consuming, and could have severely impacted field crude oil production and reduced oil storage capacity during any repair outage”.