Advanced Oil Spill Modeling and Simulation Techniques

Konstantinos Kotzakoulakisa'b and Simon C. Georgec

“CICESE Physical Oceanography,

Ensenada, Baja California, Mexico

bSINTEF Ocean AS, Brattprkaia 17c, 7010 Trondheim, Norway (current position)

cDepartment of Earth and Environmental Sciences and Macquarie University Marine Research Centre

Introduction

Oil spill modeling is an essential tool in the effort to minimize the environmental and financial impacts of accidental oil releases. It has multiple applications, spanning from oil spill preparation and response to forensic investigation and scientific research. In more detail, oil spill modeling is used in:

  • • Statistical studies in order to identify the likelihood of an area to be hit by an oil spill, the potential risk, and the corresponding impact that an oil spill will have on local species, ecosystems, and financial activities. This information is used by the relevant authorities to plan and prepare for potential oil spill events.
  • • Oil spill forecasting during an accident, in order to guide the responding authorities to decide the most effective counter measures for mitigating the effects of the oil spill.
  • • Forensic investigation for the identification of the origin of an unknown oil spill, by running reversed time simulations to determine the past trajectory of the oil spill.
  • • Scientific studies that investigate the combined effects of different environmental processes and conditions on the circulation and fate of the oil spill, especially when actual field measurements are scarce for the condition under investigation.

During the past decade, there has been intense research activity in the field of oil spill modeling. Most of the environmental processes that affect the fate of oil spills have been revisited, and new processes have been investigated. Research activity was intensified after the 2010 Deepwater Horizon disaster in order to address the lack of knowledge on the fate of deep-water oil releases and the effectiveness of response measures such as subsea dispersant injection. The Deepwater Horizon oil spill was the largest and best-documented oil spill event to date (e.g. Camilli et al., 2010; Hazen et al., 2010), and provided a large amount of valuable field data for modelers to use in the development of the next-generation oil spill models.

Although historically most oil spills happened at the sea surface, and previous generations of oil spill models treated them as two-dimensional sea-surface-only simulations, there are strong reasons that support the importance of subsurface oil releases and the need for 3D oil spill modeling in general. Subsea oil spills usually happen on the seafloor when the well head isolation mechanism (the blowout preventer) fails to stop a sudden high-pressure gas-induced surge into the wellbore. The source of the oil in these leaks is the underground oil reservoir, and the amount of oil that can potentially leak is much greater in comparison to a typical surface oil spill from an oil tanker. Additionally, the technical challenges that must be overcome to successfully stop the oil leak are greater, and usually these leaks last longer. The importance of this type of simulation is becoming even greater due to the current trend in the oil industry to explore further offshore in deeper waters, because the swallower discoveries are gradually getting depleted and deeper unexplored regions can reveal large petroleum reservoirs.

Finally, better understandings of certain environmental processes, such as the wave-induced entrainment of oil in the water column, indicate the need for 3D oil spill modeling even for the cases of sea-surface oil spills. Consequently, the contemporary modeling approach is the use of 3D modeling for both surface and subsurface oil spills.

In the following sections, modern techniques to simulate different types of oil leaks will be presented as well as some of the applications of oil spill modeling mentioned earlier.

 
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