Fuzzy-FMEA for Risk Analysis: Decommissioning an Offshore Manifold Wellhead Platform

Abstract Decommissioning is the process of dismantling a portion or all of an installation and transporting the disassembled materials to a specific location. To manage the possible and impact of risks that might arise during the decommissioning process, risk analysis is carried out. In this study, a risk assessment was conducted on the decommissioning of a four-legged jacket platform. The analysis method used was Fuzzy Failure Mode and Effect Analysis (fuzzy-FMEA), which uses a fuzzification process to identify the dominant risks and generate fuzzy-RPN (FRPN). It was found that residual hydrocarbon leakage was the dominant risk with FRPN 9, and further risk analysis was carried out using Fault Tree Analysis (FTA) to identify the root causes of the dominant risk, which were planning errors with probability 0,00026645 and Sealing failures occur with a probability of 0.00044118. Bowtie Analysis was used as a risk management tool, resulting in preventive and mitigation efforts. One of the preventive measures for the identified risks was to verify and validate the current well conditions, while mitigation efforts included narrowing the leakage area and installing a hydrocarbon detector.