ABSTRACT
In the oil and gas industry, storage tanks play an important role, ensuring a continuous flow of the petroleum based products. Interruption in their performance due to unforeseen failure and subsequent repairs can result in losses running into millions of dollars. Even the prescribed inspection and maintenance regimes cause interruptions in their service resulting in monetary losses. Although such inspections are routine in the industry, information collected from non-destructive evaluations are rarely used in planning the life-cycle management of these structures. This work proposes a framework for planning the life-cycle management of steel oil and gas storage tanks by optimizing the inspection interval (or, minimizing the inspection cost and business losses). In this, a minimum reliability-based performance criterion is selected as the constraint. The time-varying probabilistic performance of the structure (considering uncertainty in loading, material and geometric parameters) is assessed through Bayesian updating of the deterioration model based on ultrasonic thickness measurements from past inspections. This framework is demonstrated on a “Horton sphere” liquefied petroleum gas storage tank subjected to corrosion deterioration.
