Risk-based condition assessment and inspection planning for submarine pipeline systems

As an operator of a large submarine transport network Statoil is continuously seeking for improved condition assessment methods for the pipeline systems. In order to meet the overall operational objectives a risk-based philosophy has been introduced. This paper describes the principles behind the risk based condition assessment philosophy and how these principles are accounted for in the proposed assessment methodology. Failure modes with impact on the system structural integrity are discussed with respect to relevance for the operating phase and the possibility of detection during inspection. Condition assessment results are used for optimisation and planning of activities related to inspection, product monitoring and transport capacities, and for specification of corrective actions. Estimated risk and reliability parameters are used to optimise inspection activities with respect to priority of areas, selection of suitable equipment and determination of inspection intervals.