In the operation of offshore O&G there is a large number of equipment that must work continuously to keep production and safety. Part of this success depends on different type of inspection activities in active and redundant equipment. However, there are some conflicting objectives: the more one inspect equipment, the higher the reliability of the system. At the same time, cost can be increased and availability reduced in case assets have to stop. In addition, more sophisticated inspection systems have a cost and, also may demand maintenance in the instrumentation.

The present work proposes a model to evaluate this problem. The methodology is: (1) Probabilistic model of time-to-failure of assets, (2) Probabilistic model of maintenance time, (3) Probability model of the detection of failure by inspection, (4) Reliability and Availability model of the system, (5)Inflation in cost of part, labor, etc., (6) Discounted cash flow model. We use Monte Carlo simulation in order to solve this problem in a simple spreadsheet in order to demonstrate professionals that many problems can be scientifically analyzed using more simple tools.

In real world applications, the main problem consists in the estimation of the value of an inspection system to a company. We apply the model of this paper to the analysis of this problem and find the following conclusions: If probability of detection of the inspection system is 90%, the maximum investment is US$ 12.2 million; if this probability of detection is 70%, the maximum investment is US$ 9.65 million. In addition, the work will show how to use the model to solve related problems as well.

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