A New Multi-Criteria Decision-Making Tool for Subsea Oil and Gas Asset Decommissioning

Abstract The decommissioning of offshore oil and gas (O&G) facilities poses significant challenges due to high costs, operational risks, social impacts, and environmental protection concerns. Multi-criteria decision analysis (MCDA) emerges as a vital tool to navigate these complexities, enabling stakeholders to evaluate diverse decommissioning alternatives against a broad set of criteria. Existing literature lacks extensive documentation on the application of MCDA in decommissioning decisions, particularly in quantitatively evaluating the performance of different decommissioning strategies against a comprehensive set of criteria. This study introduces a novel MCDA model tailored for the decommissioning of subsea O&G assets, aiming to improve decision-making by providing a quantitative ranking of decommissioning alternatives. Employing the Preference Ranking Organization Method for Enrichment Evaluations method, the model considers 37 attributes across six criteria (safety, environment, waste management, technical, social, and economic) to evaluate several decommissioning alternatives for the Brazilian Espadarte Field. Weightings and scenarios are defined through expert consultation, enhancing the model’s adaptability and relevance to real-world contexts. The model’s application demonstrated significant efficacy, with the selected top-ranked decommissioning alternative achieving a performance indicator of 58%, corresponding to the removal of 50% of the pipeline length considered. This result underscores the model’s capacity to identify optimal compromises between competing criteria. The study contributes to the field by filling the gap in the quantitative evaluation of decommissioning alternatives, offering a robust, transparent decision-making tool that accommodates complex, multi-criteria decisions. The model provides a significant advancement in the rationalization of decommissioning strategies for O&G assets.