ABSTRACT
Whenever production systems or other installations reach their design lives, important decision must be made if the desire is to keep the system in operation. This is a highly relevant issue these days at the Norwegian Continental Shelf where many installations have been built during the 70s and 80s, the design life is typically 20-30 years and the system will remain operational another 10 or 20 years for the production of oil and gas. Consequently, important decisions about major maintenance actions must be made regarding systems, constructions and components. Alternatives could include decommissioning, total replacement, parts replacement, refurbishment or no action. However, lack of knowledge, standards and methods are some of the challenges the industry is currently facing regarding these installations. Thus there is little basis or guidance in making such decisions.
