Corrosion Control—Offshore Platforms

Increased emphasis on offshore operations and the trend to deeper waters have resulted in platform costs ranging from $2-4 million becoming commonplace. More exotic structures for use in 600–1,200 ft of water and costing $10 million plus are being designed. This magnitude of investment placed in hostile offshore environments makes control of corrosion mandatory. Corrosion is controlled with cathodic protection in the submerged portions, with protective wrappings in the splash zones and with coatings in the atmospheric portions. Principal developments in recent years have been improved coatings, built-in long-life galvanic systems and permanently mounted impressed current systems. Platform designs which minimize the number of members, decreasing the area to be maintained and streamlining the surfaces to better accommodate coatings and cathodic protection, have aided in controlling corrosion. Present technology should be adequate for deeper waters or for floating or underwater facilities projected for the future; however, improvements in methods and materials are needed for added reliability. Further application of improved coatings and expanded use of impressed current systems should lower costs in the future.