Application of failure mode, effects and criticality analysis (FMECA) to prioritize the equipment and components of the Subsea Christmas Tree System

Offshore installations spend millions annually trying to guarantee the integrity of their equipment. The challenge lies in determining where to apply the industry's always finite and limited resources to provide the greatest benefit. Risk-based inspection (RBI) was developed in the oil industry to assist in the identification of the highest risk equipment (working with the respective failure modes) and also to design an inspection program that not only identifies the most relevant failure modes but also reduce your chances of occurrence. This study is part of a project whose objective is to develop a methodology to monitor the integrity of the equipment, optimizing inspection policies, based on the risk associated with the operation of Christmas trees in subsea operations. The results of this phase of the project include the study of two typical configurations of Christmas trees and the evaluation of their FMECAs; which were based on the database OREDA (SINTEF 2015a; SINTEF 2015b), on information available in the literature and information of equipment suppliers. Finally, a classification of Christmas trees components is provided based on their risk indices. These results contribute to the performance of more effective risk analyses in the offshore industry, since data on this equipment is scarce in the literature, especially data related to their configurations, failure probabilities, inspection methods and failure detection probabilities.