Risk of Large Oil Spills: A Statistical Analysis in the Aftermath of Deepwater Horizon

Abstract

The oil spill in the Gulf of Mexico that followed the explosion of the exploration platform Deepwater Horizon on 20 April 2010 was the largest accidental oil spill so far. In this paper we evaluate the risk of such very severe oil spills based on global historical data from our Energy-Related Severe Accident Database (ENSAD) and investigate if an accident of this size could have been "expected". We also compare the risk of oil spills from such accidents in exploration and production to accidental spills from other activities in the oil chain (tanker ship transport, pipelines, storage/refinery) and analyze the two components of risk, frequency and severity (quantity of oil spilled) separately. This detailed analysis reveals the differences in the structure of the risk between different spill sources, differences in trends over time and it allows in particular assessing the risk of very severe events such as the Deepwater Horizon spill. Such top down risk assessment can serve as an important input to decision making by complementing bottom up engineering risk assessment and can be combined with impact assessment in environmental risk analysis.

Environmental Impacts of the Deep-Water Oil and Gas Industry: A Review to Guide Management Strategies

“…The greatest risk to the marine environment comes from an uncontrolled release of hydrocarbons from the reservoir, known as a blowout (Johansen et al, 2003). Risk modeling suggests that an event the size of the Deepwater Horizon incident can be broadly predicted to occur on an interval between 8 and 91 years, or a rough average of once every 17 years (Eckle et al, 2012). Several major offshore oil blowouts have occurred, including the IXTOC-1 well in the Bahia de Campeche, Mexico where 3.5 million barrels of oil were released at a water depth of 50 m over 9 months (Jernelov and Linden, 1981;Sun et al, 2015) and the Ekofisk blowout where 200,000 barrels (32 million liters) of oil were released at a water depth of 70 m (Law, 1978).…”

Oil Characterization and Distribution in Florida Estuary Sediments Following the Deepwater Horizon Spill

“…Locations are shown in Figure 1 and described in Table 1 Table 1 for site identifications and Figure 1 for sample location. Sediment samples collected July (FP) and August (NAS) 2010; 2 Rosenbauer et al [3,16]; 3 One or more analytes below detection limits; 4 Mulabagal et al [17]; 5 Hostettler et al [18]; 6 Alkane to isoprenoid ratio [14]; 7 Douglas et al [19] …”

“…The spill was the largest environmental disaster in United States history, and the largest accidental oil spill in human history [4]. Vast areas of the Gulf of Mexico were impacted by oil, including deep ocean, pelagic, and estuarine ecosystems.…”

Catastrophic oil spill analysis

“…It provides models relevant for the assessment of rare events, even outside the range of previous observations. Extreme value methodology is now commonly used in a wide range of fields, such as economic damage [7,8], finance [2,3], earth sciences [4,9,10], traffic prediction [11], large oil spills [12], etc. This paper focuses on how the statistical theory of extreme values can be applied to improve the oil spill risk analysis.…”