Maintenance grouping optimization for the management of risk in offshore riser system

Abstract Riser system failure in relation to major accidents is one of the potential undesirable events in the offshore petroleum industry. It has the potential for high consequence such as several fatalities/injuries, severe environmental impact or gross economic loss. Besides, it may be related to maintenance being insufficient, incorrect, a new hazard source or a triggering event for an accident scenario. Furthermore, there has been a paradigm shift in the design of unmanned platforms following the Piper Alpha disaster in 1988. Firefighting systems are usually not installed anymore based on the reason that the risk reduction benefit they offer to maintenance personnel is not commensurate with their frequency of visits unlike in manned facilities, i.e. a negative risk balance. In manned facilities, where such safety systems are installed, maintenance personnel are subject to major hazard exposure due to the visits required of them. Hence, there is the need to reduce the risk to personnel as much as reasonable. Maintenance grouping optimization can serve as an alternative contributor to the reduction of maintenance frequencies which should reduce the risk, but on the other hand, as the human error opportunities increase, the likelihood of making errors increases which increases risk. The main objective of this paper is to investigate how maintenance grouping optimization and the potential human error can be balanced in relation to reducing the major accident risk. The paper builds on a review of literature on maintenance optimization, human reliability and risk.