Schiehallion moorings pose inspection challenge

Phoenix Inspection Systems is providing equipment for analysis of the mooring chains for BP's Schiehallion field FPSO west of Shetland in the UK sector.

Offshore staff

WARRINGTON, UK – Phoenix Inspection Systems is providing equipment for analysis of the mooring chains for BP's Schiehallion field FPSO west of Shetland in the UK sector.

The Welding Institute (TWI) contracted Phoenix to design and manufacture a scanner, probes, and cabling - TWI developed the inspection protocol and is responsible for the testing program.

The Schiehallion FPSO is one of the largest in the world with a processing capacity of around 200,000 b/d and a storage capacity of around 950,000 bbl.

It was built at the Harland and Wolff shipyard in Belfast, and has been in service since 1998. The inspection is part of a wider maintenance program.

The FPSO is anchored by 14 mooring chains, each with diameter of 6.25-in. (15.8 cm), to piles in the seabed. Together, according to Phoenix, they comprise the largest consignment of studless mooring chain link ever produced.

The chains are due to be replaced but must be inspected to ensure they can be safely removed. Inspection is focusing on the point where the chains fix onto the ship.

Phoenix project manager Chris Gregory said: “This project posed a number of challenges in terms of equipment design as all kit must be capable of operating underwater in the harsh environment of the North Sea, yet small enough to be transported by divers and quick to assemble and fit into position.”

07/19/2011

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