Corrpro Protects Neptune Spar Hull

Corrpro subsidiary, Wilson Walton International (UK) Ltd., recently completed a contract to supply sacrificial cathodic protection and corrosion monitoring systems for Oryx Energy's Neptune Spar Hull.

The 24 million pound, steel Spar Hull, which is the first of its kind to serve as a production platform, has now been successfully installed in the Viosca Knoll 826 block in the Gulf of Mexico. The Spar Hull, which is 73 feet in diameter and 710 feet long, was built in two sections in Finland and then transported to a Pascagoula, Mississippi shipyard where the sections were welded together. Neptune was then towed out and installed in 1900 feet of water.

Among other things, Wilson Walton's expertise was required to carry out a design verification study of the external and internal cathodic protection systems. The complex structure, comprised of strakes, blisters, fairleaders, center wells and ballast tanks, required careful design consideration and sizing of sacrificial anodes.

The cathodic protection system, which was designed for 20 years, consists of approximately 660,000 pounds of sacrificial aluminum-zinc-indium alloy anodes. The anodes were all cast at Wilson Walton's foundry located in the Northeast of England at Stockton-on-Tees. Stringent quality control standards at the foundry provide long-term performance and reliability. Wilson Walton's quality assurance system conforms to ISO 9001:1994 which provides complete traceability of all materials.

To verify the effectiveness of the internal cathodic protection system, Wilson Walton was also awarded a design and supply contract for a hard-wired monitoring system. The system is comprised of arrays of dual reference electrodes (zinc and silver/silver chloride) located internally in the center wells and ballast tanks. The electrodes are hard- wired back to a monitoring panel located in the machinery deck house.

This project further demonstrates Corrpro's unique ability to provide quality, technology based systems worldwide.