APPLICATION OF THE FUZZY AHP HIERARCHICAL ANALYSIS METHOD AS A DECISION SUPPORT TOOL FOR DECOMMISSIONING SEMI-SUBMERSIBLE OIL PLATFORMS IN THE CAMPOS BASIN

The decommissioning of offshore installations is a complex decision-making problem, which involves economic, environmental, operational and safety aspects. This study develops a multicriteria decision support model to evaluate and prioritize decommissioning alternatives for semi-submersible platforms in the Campos Basin. Five mature platforms were considered as reference cases, contemplating economic-financial, environmental, safety, and technical and socio-spatial interference criteria. The model was structured by the Fuzzy Analytic Hierarchy Process (Fuzzy AHP), incorporating expert judgments through parity comparisons and triangular fuzzy numbers. The environmental and safety criteria concentrated 85.4% of the weighting. Controlled repositioning was the highest priority (31.18%), followed by partial removal (26.03%), full removal (25.33%) and maintenance for alternative use (17.45%). The results show the joint influence of the criteria on prioritization and demonstrate the contribution of the model to structured and transparent decisions in Brazilian offshore decommissioning.