Mooring systems of many long-term/permanent floating offshore installations (FOIs) are approaching the end of their original design life. Some FOI mooring systems are seeking life extension to support continued production/storage or planned tie-back. Worldwide, many offshore mooring systems have been approved for continued service.
This paper presents a state-of-the-art review of the current industry practice on mooring system life extension with an emphasis on fit-for-service technical assessment but excluding the project economic considerations for decision-making. The objective is to initiate an industry-wide approach to improve technical assessment for mooring life extension by identifying gaps and challenges.
A comprehensive survey was carried out on the available policies from the regulatory authority and technical guidance from the industry. The major technical challenges are discussed covering baseline information collection, in-service mooring inspection, damage/degradation assessment of components, mooring design re-analysis, and remaining life prediction. Recommendations on technological development, industry guidance, and life cycle integrity management were made to advance the current industry practice of mooring system life extension.