Application of Fuzzy Set Theory and Expert Judgement in Reliability Analysis of the Arctic Oil and Gas Facilities

摘要

Reliability analysis has various applications in oil and gas processing facilities such as identifying the bottlenecks of the system,quantitative risk assessments,improving system availability and throughput capacity,and optimising maintenance strategies.Reliability performance of a system can be described as a function of operation time and a series of operational conditions.For this purpose,a range of reliability data is required,based on which the reliability function can be modelled.One of the challenges in reliability analysis of Arctic oil and gas facilities is lack of adequate reliability data.The available historical reliability data gathered in normal climate regions may not be appropriate,as they do not include the effects of harsh Arctic operational conditions on system performance. In this study,expert judgement process is used to modify the mean-time-between-failure(MTBF)of the equipment to include the adverse impacts of Arctic climatic conditions on system performance. Additionally,fuzzy set theory is used to cope with the uncertainties of experts’opinions in both the component-and system-level analyses.For this purpose,a methodology is presented to perform a fuzzy fault tree analysis(FTA)for system reliability assessments.This methodology is further illustrated by a case study.Based on the results of this study,operational conditions can have various adverse effects on the performance of different components.Additionally,expert judgement can be used as an effective method for system reliability analysis,particularly in the design phase where historical data is scarce.