A Decision Support Model for Platform Decommissioning: Successful Applications in California and Implications for Worldwide Use

Abstract

As companies around the world plan for the future decommissioning of oil and gas platforms, a case study from California provides a model in terms of both process and the use of decision support tools. The question of how to decommission California's 27 offshore oil platforms, like many issues related to offshore oil and gas in California, began as a major public controversy. We created a decision analysis software tool (PLATFORM) to clarify and evaluate decision strategies as part of a larger policy analysis conducted for the California Ocean Science Trust. The in-depth analysis focused on two main optionscomplete platform removal and partial removal to 85 feet below the water line, with the remaining structures to be converted in place as an artificial reef to preserve their biological value. PLATFORM was key in structuring and performing analyses of the impacts of each option (e.g., on costs, fishery production, air emissions) and greatly improved the team's productivity. Sensitivity analysis showed that different preferences, especially about the importance of strict compliance with lease agreements, is much more important in selecting the preferred option than is uncertainty about specific outcomes, such as decommissioning costs. The project's results affected the decision to pass legislation enabling an expanded California Љrigs-to-reefsЉ program, which includes a mechanism for sharing cost savings between operators and the State. The decision model presented here for the 2016 SPE International Conference and Exhibition on Health, Safety, Security, Environment and Social Responsibility can be adapted readily to other marine environments and could support regulatory decision making for decommissioning worldwide.