Life Extension of Ageing FPSO and SPM Calm Buoy Mooring Chains Under Corrosion Effects - Part 2A

This study unveils the recent challenges that mooring chains used for station keeping of floating assets face while in operational marine environment. Considering the extremely harsh operating environment, the mooring chains on floating production, storage and offloading (FPSO) and single point mooring calm buoy (SPM) will definitely undergo degradation and deterioration over time. Although, general/uniform and pitting corrosion has been implicated as major cause of mooring chain degradation. Ageing and age related challenges such as pits, wear and corrosion wastages across the mooring chains intergrip, side and straight bars were key considerations for life extension evaluations since it weakens the strength of the chains. The biological phenomenon that causes pits on mooring chains were highlighted. Regrettably, the scarcity of real time corrosion wastage data has made researchers to adopt data from laboratory in corrosion coupon for the purpose of study. Although, laboratory data are usually under control, and hence researchers are looking for more realistic data from marine corrosion environment. It was observed that corrosion wastages are known to alter the geometry of mooring chains but not the chemical and mechanical properties. It was observed that real time corrosion wastage data from a floating asset in marine environment is key to drive life extension decision making. However, it was observed that there are still limited information as regards the type of data to measure, their collation, analysis and interpretations towards the ultimate goal of mooring chains mitigation strategy for longevity.