Session: 02-12-01 Reliability Based Maintenance and Inspection Planning

Submission Number: 157625

Decision-Making Approach to Support the Selection of Remotely Operated Inspection Methods of FPSO Tanks 

The inspection of structural members that are part of cargo or ballast tanks of Floating Production Storage and Offloading (FPSO) platforms are usually executed according to the requirements listed in the classification societies rules. The inspection is executed employing operators who need to climb the tank walls in order to carry out inspection at points considered critical from the point of view of developing degradation processes. Once the visual inspection has detected a degradation process, non-destructive inspection must be executed to define the extension of the degradation. Based on that information the ship owner´s can evaluate the structural strength and the need for maintenance.

However, besides being time consuming, the inspection based on human operators can put into risk the human life. Taking in view the reduction of human exposition to risk some automated techniques are being tested aiming their use for structural inspection.

This paper presents a literature review about the possible automated techniques that may be used in the inspection of FPSOs tanks structures aiming at detecting the main degradation processes that affects those structures such as crack propagation and corrosion. The review includes the application of crawlers, drones and other robotics procedures. The main limitations associated with those methods are discussed.

Based on that review a decision-making procedure is proposed to select the most suitable inspection procedure to be used in the inspection of cargo and ballast tanks aiming at increasing the inspection operational safety and maximizing the inspection effectiveness. The criteria used to rank the inspection methods are presented and include degradation detection capability, autonomous operation, maturity of the inspection method, inspection costs among others.

The method is applied on the definition of inspection procedure of a typical FPSO tank aiming at defining its applicability in a real case. The most suitable inspection method is selected based on the elicitation of experts opinion through the application of a questionnaire based on the decision-making procedure previously developed.

Presenting Author: Gilberto Francisco Martha De Souza University of São Paulo

Presenting Author Biography: Prof. Dr. Gilberto F. Martha de Souza is a Full Professor at the Department of Mechatronics and Mechanical Systems Engineering at the Polytechnic School of the University of São Paulo. He is currently head of the Reliability and Risk Analysis Laboratory of that department. Dr. Martha de Souza researches reliability, maintainability, and risk analysis of critical systems such as power plants, ships systems, and defense products.