N E W S   R E L E A S E   from FURMANITE  INTERNATIONAL

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FIL/0704
8 May 2007

Permanent repair technology for offshore platform

Composite repair technology from Furmanite, the technical services company geared to maximising asset uptime, has provided permanent rehabilitation with no disruption to operation to a vessel on the Leman Alpha platform in the southern North Sea (72km north east of Lowestoft).

External corrosion had caused wall thinning and needed repair and strengthening – the traditional solution to which would have been to shutdown and weld. Instead, Furmanite was able to restore full structural strength and pressure integrity with a composite repair, which could be undertaken without disruption to production.

The permanent repair (10 year design life), engineered to a design pressure of 5 barg and temperature of 40°C in line with the vessel operating conditions, was undertaken on-line while the platform remained live, using carbon fibre and epoxy resin composite technology. These materials provide exceptional strength (up to ten times that of steel, yet lightweight at less than a quarter the density), and require no prefabrication or hotwork.

The repair process involved surface preparation (critical to achieving a satisfactory repair) using grit blasting to a specified roughness and cleanliness to achieve an optimum bond. This was followed by an e-glass layer as a tie coat, followed by a number of layers of epoxy resin-impregnated carbon fibre, providing a patch repair less than 6mm thick over a 1.4 by 10.2 metre area of the vessel underside, with a specified overlap onto sound metal in line with design calculations, and incorporating a taper to the precise ratio specified in the repair design. A sacrificial peel-ply layer takes up excess resin and provides (when removed after curing) a surface that can be painted or coated as required.

The vessel end caps, 2 inch nozzles and saddle supports were also incorporated into the repair, requiring varying numbers of carbon plies to achieve the necessary repair strength. The repair technology was also able to overcome issues of difficult access working in a confined area under the vessel – a further advantage of using composites, which can be applied successfully in challenging conditions with only a hand’s width clearance required.

“Vessel composite repairs involve complex engineering, taking factors such as further erosion, axial loading and vessel content properties into account,” Furmanite business manager Paul Smith comments. “The awkward geometries of the nozzles and saddle supports are also challenging to apply.

“Composites technology provides significant advantages but requires skilful application to provide a successful, long term, high performance repair,” he adds. “The work was carried out by highly trained technicians, enabling us to provide a fully validated repair.”

For further press information contact:
Sarah Manwaring-White, Keep in Touch Ltd,
Tel: +44 (0)1451 844 488  Email: sarah_mw@keepintouch.co.uk
Issued on behalf of Furmanite International