ABSTRACT
Decisions regarding inspection intervals for well barriers are often made with respect to traditional PF modelling. The optimal inspection interval is then the one that minimises the expected costs of inspection, replacement and potential accidents. In this paper we argue that such an approach is not in general appropriate, and is better replaced by a framework that provides different types of decision support for various types of decision situations. The new framework acknowledges that the weight given to expected costs is appropriate only in situations with low vulnerability and with a low score on a ‘Probability of barrier failure-Strength of knowledge-Index’ (PS-index). In other situations ALARP should be the ruling principle. An example is used to illustrate the practical implications of the framework.
