This paper presents a reliability assessment methodology for fixed offshore structures, considering models and characterizations associated with the criteria developed for design and requalification of platforms in the Bay of Campeche as well as the evaluation of global reliability index of an offshore structural system. A comparison of the analytical results of some offshore structures obtained from the application of this methodology is included considering also the influence of reliability updating after inspection in order to set up an optimal inspection planning.
About 200 marine platforms that produce in excess of 2 million barrels of oil and 1.5 billion cubic feet of gas per day are installed in the Bay of Campeche. Therefore, it is necessary to ensure structural integrity so as to maintain safe production of those platforms by means of an adequate reliability assessment. A risk criteria was developed for design and requalification of the offshore structures installed in the Bay of Campeche, considering probability based risk assessment and management methods by characterizing operating and environmental loading and platform loading capacities (Bea, 1997a, 1998a). Once defined the consequence of failure in terms of cost as well as the probability of failure of the offshore structures, it was possible to establish a relation between the level of risk of the marine platforms of the Bay of Campeche and the level of risk accepted by the international codes. A classification of fixed offshore structures located in the Bay of Campeche was developed in order to define target reliabilities based on economic, historic performance and standards of practice approaches. This classification divided the platforms into four categories considering the consequences associated with the lost of safety.