Optimization of Corrosion Allowance for Substructure Splash Zone Area

Corrosion in Marine and Offshore Structures such as platform substructure is one of the issues to be considered during the design stage. The current corrosion allowance (CA) at the splash zone area for platform substructure in Malaysia is 12mm based on 30 years design life without considering the effect of coating performance and cathodic protection for the submerged splash zone area. This issue is crucial because many of the around 200 platforms and other marine structures in Malaysia are reaching their design life (DL) and a lower corrosion allowance would mean that they can continue to be used without strengthening the structures. The main objective of this study is to optimize the corrosion allowance for substructure splash zone areas for tropical climate recommended to new facilities in tropical climates (seawater surface temperature >20°C, e.g. Malaysia, Indonesia, Myanmar, Vietnam, etc). Herein, a study is conducted to reduce the requirement of corrosion allowance to 6mm on thickness for primary members of the jacket by gathering and correlating all the available codes and standard, analysis of actual field data, correlation between coating and cathodic protection effect towards splash zone. The implementation of the optimized corrosion allowance would benefit the owners of the marine structures such as oil and gas companies in terms of reduction in material and fabrication cost.