An oil spill risk analysis for the South Atlantic Outer Continental Shelf lease area

ABSTRACT 2017-051: The U.S. Department of the Interior (DOI) Bureau of Ocean Energy Management (BOEM) maintains a leasing program for commercial oil and gas development on the Outer Continental Shelf in U.S. territorial waters. To evaluate the potential impacts of these activities, BOEM performs oil spill risk analysis (OSRA) using, in part, a statistical model for estimating the movement of hypothetical oil spills on the ocean surface based on model-generated surface wind and surface current. OSRA examines oil spill risks over long periods of time ranging from 5 years to decades. The latest OSRA analysis estimated the contact probabilities of oil spills in the Gulf of Mexico (GOM) region by modeling over 40 million hypothetical oil spill trajectories over extended areas of the U. S. continental shelf and tabulating the frequencies with which the simulated oil spills contacted designated natural resources within a specified number of days. The modeled ocean currents and wind fields used in the GOM analysis are from 1993 to 2007 (15 years). The OSRA model was also applied to analyze the contact probabilities of the Ixtoc Oil Spill, which happened on June 3, 1979 in the Bay of Campeche of the GOM and lasted for 10 months. The Ixtoc I Oil Well suffered a blowout, resulting in one of the largest oil spills in history and 3 million barrels of oil spilled. The OSRA model was applied to simulate particle trajectories released at the Ixtoc location using the same GOM current and wind field data from 1993 through 2007. The model results for the Ixtoc simulation were consistent with the descriptions of the oil spill by Hooper (1982), which shows that the OSRA model can provide a reasonable projection of the contact probabilities of hypothetical oil spills.

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Oil-Spill Risk Analysis for Assessing Environmental Impacts

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2003-1-1125 ◽

2003 ◽

Vol 2003 (1) ◽

pp. 1125-1129 ◽

Cited By ~ 4

Author(s):

Zhen-Gang Ji ◽

Walter R. Johnson ◽

James M. Price ◽

Charles F. Marshall

Keyword(s):

Risk Analysis ◽

Gulf Of Mexico ◽

Continental Shelf ◽

Oil Spill ◽

Ocean Currents ◽

Management Service ◽

Numerical Schemes ◽

Outer Continental Shelf ◽

Oil And Gas Development ◽

Runge Kutta

ABSTRACT The Minerals Management Service (MMS), an agency of the U.S. Department of the Interior, maintains a leasing program for commercial oil and gas development on the Outer Continental Shelf in U.S. territorial waters. The MMS performs an oil-spill risk analysis (OSRA) using, in part, a statistical model of hypothetical oil-spill trajectories. The OSRA Model is driven by analyzed sea surface winds and model-generated ocean surface currents. Instead of focusing on individual oil-spill events, the OSRA examines oil-spill risks over long periods of time, ranging from 5 years to decades. The OSRA Model calculates thousands of oil-spill trajectories over extended areas of the U. S. continental shelf and tabulates the frequencies with which the simulated oil-spills contact the geographic boundaries of designated natural resources within a specified number of days after the simulated spill events. A key element of OSRA Model runs is the particle trajectory simulation based on wind velocities and surface ocean currents. It is critical that the trajectory model has a numerical scheme that is stable, accurate, and efficient. Currently, two numerical schemes are incorporated into the model: the Eulerian scheme and the 4th order Runge-Kutta scheme. To test the numerical schemes, a set of analytical solutions to the Navier-Stokes equations is developed. The analytical velocities and particle trajectories are compared with the numerical solutions from the two numerical schemes. The stability and efficiency of the two schemes are discussed. Applying the model to the Gulf of Mexico using 9 years of winds and ocean currents, we find that the OSRA Model with the 4th order Runge-Kutta scheme is much more efficient and able to better represent the circulation patterns and particle movements in the Gulf of Mexico.

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