Knut Øien

The basic concepts of failure analysis

This paper discusses basic concepts of failure analysis and gives advice on how to interpret, e.g., function, failure, failure mode, failure cause, and failure effect, using a gate valve as an example. A general approach to identification and classification of functions and failure modes is presented and the various steps of failure analysis are discussed. The OREDA (Offshore Reliability Data) database is used to illustrate the interpretation of the basic concepts. Limitations in the use of OREDA are pointed out and proposals for enhancements of this database are given.

Recommendations on the use of expert judgment in safety and reliability engineering studies. Two offshore case studies

Abstract This paper provides guidance on the process of establishing input data to safety and reliability engineering analyses when no or little field data exist, and expert judgment is required. Some recommendations are directly related to a discussion of basic requirements for scientific work. Further, two case studies are discussed in order to highlight some actual problem areas that are experienced when using expert judgment, and some recommendations for handling these problems are given. The first case describes how expert judgment was used to analyse the safe operation of an umbilical on a semisubmersible drilling rig, and the second case is related to establishing generic failure rates/probabilities for components of offshore safety systems.

Assessment and comparison of two early warning indicator methods in the perspective of prevention of atypical accident scenarios

Abstract Some severe major accidents occurred in Europe in recent years (e.g. the Vapour Cloud Explosion at Buncefield in 2005), which were not foreseen by their site “Seveso-II” safety reports. Detailed analyses of such “atypical” scenarios demonstrated that they are the result of a number of failures at different technical and organizational levels. Thus, their prevention is a major challenge and must be coordinated through different kinds of approaches, among which improved early detection plays an important role. Proactive methodologies for the development of early warning indicators can unveil early deviations in the causal chain. Two examples are the Resilience-based Early Warning Indicator (REWI) method and the so-called “Dual Assurance” method. The aim of this study was to analyse the possible integration of early warning indicators in the hazard identification process. A Buncefield-like site was analysed to obtain indicators that were compared with the actual causes that led to the accident at Buncefield (and to similar accident scenarios). The results show that indicators from both methods could have prevented the accidents from happening. However, one main difference is related to the issue of hazard identification, which is fundamental for the prevention of atypical accident scenarios. The REWI method is not dependent on the outcome of the hazard identification process. Instead it provides complementarities to the first prevention approach (improved identification of atypical scenarios), demonstrating that a mutual activity would be an effective strategy in which human, organizational, cultural and technical factors are treated in an integrated manner.

Remote operation in environmentally sensitive areas: development of early warning indicators

Exploration and production of oil and gas in certain sensitive areas such as the Barents Sea and Lofoten is controversial and further expansion depends on the ability to avoid harmful spills. One way of improving the ability to avoid such spills is to use early warning indicators. The objective of the work presented in this paper is to describe and compare strengths and weaknesses of different approaches for the development of early warning indicators. The approaches that have been compared are: safety performance-based methods; risk-based methods; incident-based methods; and resilience-based methods. There are pros and cons with all methods. All methods are very favorable with respect to some characteristics and at the same time very unfavorable to some other characteristics. They are also different in terms of scope and depth of analysis. This suggests that we should be flexible with respect to the choice of methods, and preferably use more than one method. Thus, the main conclusion is that it is favorable to have the possibility to use several different methods for the establishment of early warning indicators.

Benefit-risk trade-offs in retrospect: how major stakeholders perceive the decision-making process in the Barents Sea oil field development

This study provides an analysis of risk-benefit communication and participation of the siting process for the Norwegian Goliat oil field development, within the context of a revised model of the International Risk Governance Council’s framework. The main objective of the study is a retrospective review of the decision-making process seen through the lenses of the major stakeholders involved in this process. The research design used qualitative methods of empirical research including stakeholder interviews during a five-day period in 2011 in Northern Norway. Results showed that the siting process of Goliat was dominated primarily by the issue of benefit sharing. In view of potential risks to such oil development, local stakeholders felt entitled to some compensation in terms of shared benefits. However, over the course of time the high hopes that these benefits would materialize and provide additional benefits to the communities which would then be fairly distributed among the beneficiaries have been disappointed. We review the reasons behind these results as well as formulate recommendations regarding potential improvements to the risk-benefit communication process in addition to future siting processes.

Development of a Scenario Analysis Method for the Analysis of Complex Changes

In this paper we describe a method for the analysis of safety effects of complex technical and organizational changes. The method is based on CRIOP 2003, which is a scenario analysis method focusing on the possibility and ability of the control room operators to handle crisis situations.

Barrier Change Analysis Method

“Change is the mother of twins — progress and trouble” [1]. In some areas of operation, change is the very mechanism for survival. In the exploitation of non-renewable resources, like oil and gas, the operations and maintenance costs will at some point exceed the revenues. In order to maximize the overall exploitation of the reservoir, the cost side has to be reduced and the key word is“change” — technical, operational, and organizational changes. In particular remote operation and de-manning are relevant measures to extend the tail production phase. Another topical issue is major replacements of old equipment, e. g., the safety and automation system, due to lack of spare parts and problems in maintaining sufficient competence on yesterday’s systems. The central issue then, from a safety perspective, is how to analyze such complex changes with respect to their effect on the risk of accidents (the“trouble” part of change).