Risk assessment for offshore installations in the operational phase

Risk assessments for offshore petroleum installations have for more than 20 years focused on development of new installations or major modifications, using both qualitative and quantitative risk assessments. The risk assessments have often, especially the quantitative studies, placed an emphasis on major hazards. There is now focus on how risk assessments may be used most efficiently for installations in the operational phase. In this paper we review the challenges for use of risk assessment studies for installations in the operational phase, with the main emphasis on quantitative studies. The focus should mainly be on aspects that are available for influence in the operations phase, so-called free variables. When these are of a different nature from those that apply in the development phase, this should have strong impact on the studies being conducted. However, these changes to analytical approach have yet to be fully implemented.