ATLANTIC MARINE SOPC ANODE RETROFIT 2011

Atlantic Marine’s planned work programme for the complete rehabilitation of the subsea section of SaltPond Offshore’s Mr. Louie production platform, offshore Ghana and remedial works on the superstructure jackets in the four years preceding 2012 was based on the adherence of a consistent maintenance schedule of key and pertinent assets on a timetable for the continued integrity of the production platform.

CONSIDERATION

Humphrey Okposo has presented to the management of SaltPond Offshore Producing company that protection for their facility is due as installation of the last cathodic protection had expired, hence the platform was now not cathodically protected. The challenge now, as he explained to the company’s management is that it is imperative that there should be electrical continuity of all metal components, as in all immersed structure as the Mr. Louie production platform, otherwise the resultant differential protection might cause a rapid deterioration of the bonded and un-bonded surface of the parent metal. A gradual and consistent dismemberment of the structure will as a result begin to occur.

Previous cathodic protection installed by Atlantic Marine through the subsea section of the total area of 18,882sqft, in 90fsw of the Mr. Louie production platform in January 2002. Protection applied had the potential electrochemical output of 355Amph/Ib in a total weight structure of 3,360Ibs installed.

As the surface area had a program of topside coating, current density requirement of the subsea section is assumed to be 2mA/sqft. Complete protection was to be provided for 17,280hours. Differential protection of up to 1,000hrs had now been created, as complete protection would have lapsed as at early January 2013.

Differential cathodic protection is a grave chemical reaction that is created after the expiry of a cathodic protection system to cause dismemberment and weakness of the steel structure.

It is advised that this situation is corrected immediately, so as not to undo the protection which earlier installations and corrosion systems have consistently provided in the last few years.