Assessment method for review of existing maintenance strategies based on reliability, availability, risk, and cost parameters

Abstract

Maintaining assets is a fundamental part of any industrial facility. Oil and gas operators are often using advanced maintenance strategies, but the strategies are usually built preoperation and not systematically updated later in-operation. Still, the operators often record the necessary maintenance data that would allow them to optimize these strategies. The lack of this experience has been challenging in the recent years were operators have had to cut back on maintenance without truly knowing the consequence of these cuts. Another issue is the silo thinking between the different disciplines, operator personnel, and service providers. They are often working towards their own solutions, without sharing information and experience that would allow for a more optimal solution. A full overview of economical, technical, and risk figures are of great benefit for the decision maker and subsequently the end result. Apply Sørco recognized these problems and proposed this as a master thesis. The objective of the thesis was to develop a cost-risk-benefit method to assess existing maintenance strategies and support maintenance optimization (benefit in terms of reliability and availability). The assessment method contains reliability engineering, costing, and risk analysis techniques to present an overview of both performance and possible improvements. In addition, the method suggests considerations of internal and external elements under continuous change that affects feasibility and performance of the maintenance. The output of the assessment method works as a foundation for optimizing maintenance strategies, and as a justification method through the comparison of the existing and the optimized strategy. The method is able to show performance and possible trends, which combined with changing internal and external elements should enable optimization of maintenance strategies and asset performance. The performance is not able to tell what’s wrong, but shows if there is something wrong. Trends may show the problem, but the root cause could stem from internal or external factors. The assessment method is therefore a great tool for managing and controlling performance, due to considering all aspects. The assessment method was tested on a real case supplied by Apply Sørco. The assessment method showed promising results and made up a good overview of the existing maintenance strategy. It allowed the analyst to assess and review the existing maintenance strategy from a real case, based on the performance and the failure trends. The results from the assessment method showed that the test case would benefit from an update. The updated strategy was expected to perform better in all analyzed aspects and was therefore recommended. While there exist several management methods that include an analysis and improvement part, they seldom explain how to perform this part or what to include in the process. This method proposes techniques, prerequisites and guidelines for performing the assessment, and makes for a more defined method.