Abstract: The essence of the complex oil and gas production equipment can be considered as an open system. There exist coupling relationship between various parts of the equipment and also different faults, which result in multiple fault propagation paths. Considering the safety, benefits and maintenance loss, parameters such as downtime losses, minimum maintenance costs, corrective, preventive and opportunistic replacement costs, are analyzed comprehensively to investigate the influence of different maintenance strategies. An opportunistic maintenance model based on fault preventive defense is proposed in the paper, which determines the defensive positions, time, styles and criterion, developing a failure early-warning maintenance mechanism of oil and gas production equipment. It helps to convert the negative random factors caused by single fault to a favorable opportunity of fault prevention for other components in advance, so the overall fault losses can be reduced.

Key words: Global optimization, Maintenance simulation, Opportunistic maintenance, Risk level