Effect of repair factors on multi-level optimization of maintenance planning for corroded pipelines considering different failure modes

Resumo

The use of pipelines for transporting fluids is essential and has been growing
significantly in the oil and gas industry. Although pipelines are one of the safest
methods to transport these materials, it is necessary to consider the risks of failures in
the design, as such incidents can cause considerable damage to the population, the
environment, and the infrastructure. In this context, the aging of the pipeline network
has been extensively studied, and corrosion is one of the main concerns regarding
structural integrity. Therefore, adequate maintenance planning is essential to ensure the
safety and cost-effectiveness of the sector, as effective pipeline integrity management
can reduce expenses and maintain safety standards throughout the operational life of the
pipeline. In this scenario, inspection and maintenance planning research has become
increasingly relevant; recent studies have utilized reliability analysis through Monte
Carlo simulations to define optimal maintenance schedules for corroded pipelines,
aiming to minimize operational costs associated with pipeline management. This paper
investigates the influence of repair factors on the estimated total costs of inspection
schedules optimized for a given number of inspections, considering only one failure
mode and the combination of these (small leak, burst, and rupture). For this, a
combination of methodologies already validated and presented in previous works is
used, in which a multilevel optimization is carried out by predefining an upper limit for
the maximum failure probability, which will act as a constraint on the optimization
problem. The reliability analysis will be performed using Monte Carlo simulations,
which are commonly used in the literature. Finally, preliminary results indicated that the
failure mode strongly influences the final cost, so the results considering only one
failure mode are expected to differ considerably.