The use of control chart for a continuous monitoring of the water-oil ratio in fields of the Potiguar basin/Brazil

Resumo

Nowadays, petroleum is the most used energy source in the world, however it also produces a great volume of a residue denominated produced water (PW). This water has no commercial value and requires treatment, due to potential contaminants in its composition, in order to be destined for disposal or reinjection during recovery methods. In this way, the produced water management needs specific process support it, becoming costly. Therefore, the present work proposes a continuous monitoring methodology of the water-oil ratio, aiming to subsidize the field viability analyses. Once that the water-oil ratio data are auto-correlated, some adjustments are needed before the application of the control charts. Therefore, ARIMA models were adjusted to the data, evaluating the accuracy of the models, then, the control charts were built based on the residues. In this paper, the type of control charts considered was a Shewhart for the averages. The performance of the chart was evaluated through simulations and it was determined that it is efficient to detect big deviations, but slow to small deviations.