Optimization of vibration analysis inspection intervals for an offshore oil and gas water injection pumping system

Maintenance is often considered a ‘necessary evil’ rather than a means of delivering value to owners and operators of physical assets, and means that maintenance seldom has the requisite importance and focus required. Optimal maintenance allows the delivery of maximum productivity and profit at minimum costs, and there are two ways of determining a nominally optimal maintenance solution: qualitative and quantitative optimization. Condition-based maintenance has long been recognized as an effective strategy for maintaining critical plant, and involves the regular inspection of equipment condition to determine the need for remedial maintenance activities. The periodicity at which inspections takes place is often ill-determined and appropriate quantitative analysis seldom takes place. Such an approach often leads to excessive direct costs and can result in significant indirect costs if asset failure is considered. This paper presents a solution to this problem; the quantitative delay-time maintenance model allows the determination of the optimum condition-based maintenance inspection interval. This approach is illustrated by the application of the model to the optimization of vibration analysis intervals for an offshore oil and gas water injection pumping system and demonstrates advantages when compared with conventional qualitative approaches.