An article by Max Henrion in the February 2015 issue of OR/MS Today described the decision analysis used to determine the best option for decommissioning 27 offshore oil and gas platforms off the coast of Southern California. A complete report on the analysis can be found here.
The article illustrates two of the three critical perspectives on decision making: (1) the problem-solving perspective (what do with the platforms) and (2) the decision-making process perspective (how to make the decision).
From the problem-solving perspective, the decision is actually 27 decisions, one for each platform. The article lists multiple options in three categories: complete removal, partial removal, and leave in place for reuse. Within each category were multiple alternatives.
The attributes used to evaluate the alternatives were costs, air quality, water quality, impacts on marine mammals, impacts on birds, impacts on the benthic zone, fish production, ocean access, and compliance with lease terms.
Based on the stakeholders' preferences, the analysts created a multi-attribute model. For each platform, each decommissioning alternative was given a score (on a 0 to 100 scale) for each attribute, and the scores were combined using a weighted sum. The alternative with the best total score was identified as the best for that platform.
From the decision-making process perspective, the process was an analytic-deliberative one, and the analysis involved many traditional tools, including influence diagrams, decision trees, sensitivity analysis, and swing weighting.
A multidisciplinary analysis team began by identifying a wide range of options but determined that some were technically or legally infeasible. They then evaluated the remaining ones in more detail.
This included creating quantitative models to determine how decommissioning would affect fish production and ocean access. They constructed a computer program that lets a user update the scores and weights. They conducted sensitivity analysis to determine how uncertainties in costs and the impact of changing the weights on the attributes. The most influential factor was the weight on compliance; a higher weight on compliance increased the desirability of complete removal.
After completing its analysis, the team then issued its report to its client and released its model to the stakeholders. The deliberative part of the process included a series of meetings with stakeholders and the public and policy discussions that led to legislation that enables partial removal, the alternative that reduces both environmental impacts and costs.
I recommend the article as a case study of the analytic-deliberative process and an illustration of how decision analysis tools can be used.
Tuesday, March 31, 2015
Thursday, March 5, 2015
Hardcover version available in April.
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