Evaluating alternatives for decommissioning California's offshore oil and gas platforms

Abstract

This paper introduces a series of 6 additional papers in this issue that describe an in-depth analysis of options for decommissioning oil and gas platforms offshore southern California. Although current leases require lessees in both state and federal waters to completely remove all production facilities and restore the seafloor to its pre-platform condition, other options have emerged since these leases were signed. Laws and regulations in other jurisdictions (particularly in federal waters) have evolved to allow a number of other uses such as aquaculture, alternative energy production, and artificial reefing. In response, the California Natural Resources Agency initiated an effort to investigate the issues associated with these and other decommissioning alternatives. The papers in this series are the result of the second phase in this process, a broad investigation of the engineering, economic, and environmental costs and benefits of the most feasible and likely options. In addition to the project's final report, the authors produced an interactive mathematical decision model, PLATFORM, that enables users to explore the implications of different decommissioning projects and options, as well as the effects of different approaches to valuing the associated costs and benefits.

Oil platforms off California are among the most productive marine fish habitats globally

“…Although platforms represent a small contribution to the overall hard substratum in California (18), these structures may be providing a large amount of the hard substrate below a depth of 50 m (17). Therefore, deeper-water platforms may provide considerable hard substrate in soft-bottom outer shelf regions (36). Furthermore, it is clear that juvenile rockfishes are recruiting to and being produced on platforms over multiple years, and these habitats may be valuable in rebuilding populations of bocaccio (Sebastes paucispinis), an overfished species in the region (29).…”

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

“…Partial removal may include enhancing the resulting artificial reef with quarry rock at the base of the platform. Each of these decisions involves a number of tradeoffs (Bernstein et al 2010). For example, explosives can be a cheaper method of cutting platform structures underwater, but may increase risks to marine mammals.…”

“…Thus, platform operators are concerned about the large expense of complete removal, which may exceed $1 billion (in 2009) for the 27 platforms (Proserv Offshore 2010); air quality regulators are concerned about the air emissions from decommissioning activities (Cantle and Bernstein 2015); some resource managers seek to preserve the rich ecosystems and biological production associated with platforms (Pondella et al 2015); and some environmental advocates prefer a strict compliance approach that would hold operators to the terms of their original leases (Bernstein et al 2010). The strength of feeling associated with these perspectives in southern California stems in part from the disastrous 1969 Santa Barbara oil spill caused by a blow-out during drilling operations from Platform A.…”

“…We were members of the team contracted by OST to conduct the analysis (Bernstein et al 2010;Bernstein 2015). We describe the use of a mathematical decision model (PLATFORM) for the analysis and summarize its results and insights.…”

“…The model enabled an integrated synthesis of a full range of competing outcomes and values and provided all stakeholders with an analytic tool that supports examination of tradeoffs across a range of decision options. A key function of the model and the overall assessment (Bernstein et al 2010) was to help resolve long-standing conflicts by assembling a comprehensive summary of existing science relevant to decommissioning decisions. We adopted methods from decision analysis, including:…”