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Marine Sciences Division

Fossil Energy

Spill Transport and Risk

Environmental Licensing

As global energy demands continue to increase, easily accessible petroleum resources are being depleted. To promote US energy independence, domestic exploration may include deep ocean and Arctic environments. Oil production in waters of the US Outer Continental Shelf is likely to increase in the foreseeable future. While deep-water exploration represents an important resource for growing US energy demands, the Deepwater Horizon blowout of 2010 highlights the many uncertainties about spill remediation, and in particular the interplay of oil leaks, dispersants, and biodegradation in the cold and high pressure environment of the outer continental shelf. While much shallower, Arctic environments introduce other challenges, particularly the presence of solid, broken, and frazil ("slush-like") ice that can hide spills and interfere with traditional cleanup tools.

Oil dispersants are mixes of chemicals used to enable crude oil to mix with water. These are used to reduce the droplet size of the oil, allowing for faster weathering, dispersion throughout the water column, and greater accessibility of the oil to water, dissolved oxygen, and microorganisms in order to promote biodegradation. Current models for dispersant use assume a high degree of continuous mixing, high oxygenation, warm temperatures, sunlight, and surface pressures. Very little data exists that characterizes how oil mixed with a dispersant behaves under the cold, low-turbulence, dark, low oxygen, and high pressure environments of the deep ocean.

Chemical herding agents are used to corral oil by pushing inward from the periphery of the spill. Herding agents are low-viscosity chemicals that spread rapidly to near monomolecular thicknesses on the surface of calm water. The leading edge of the spreading film changes the interfacial forces of the oil-water interface, causing separate patches of oil to be attracted to each other and form thicker slicks. The herding agent may also exert enough force to push against an oil slick. The objective of using herding agents is to push oil slicks in a particular direction or to concentrate oil into a smaller surface area with a slick thickness suitable for in situ burning or skimming.

Spill Response: Deep Ocean and Arctic Research

Spill response: deep ocean and Arctic research

Pressure reactors at MSL are built to handle corrosive seawater and brines and able to simulate deep ocean environments up to 2 km in depth and 3000 psi in pressure.

Spill response entails a combination of multiple strategies to minimize environmental effects, depending on environmental conditions, oil movement, and changes in the oil itself over time. Often the choice to use one strategy, such as a dispersant, might have a negative impact on the ability to later use a different strategy such as herding or skimming. MSL scientists are conducting research to identify and develop materials that could provide multiple modes of action under a wide variety of conditions to complement or support many cleanup strategies, and which could be prepared and stored for extended periods for rapid deployment.

To address challenges presented by deep-water settings, MSL is using its hyperbaric research facility to simulate the high pressure, cold, dark, and oxygen depleted environment of the deep ocean. Variable mixing capabilities allow the simulation of initial mixing at release points followed by the stratification and low-turbulence conditions found at depth. Scientists at MSL are examining oil and oil dispersant mixtures at simulated ocean depths up to 2 km, where the pressure is around 3000 psi. The objective is to generate data about the physical and chemical properties of oil or oil dispersant mixes and rate of biodegradation under the high pressure, low temperature, and low mixing conditions found at extreme depths to inform better response planning. A separate set of carefully designed and non-pressurized experiments is examining the effects of oil droplet size on biodegradation. Data from these experiments supports a collaborative effort with the National Energy Technology Laboratory (NETL) in Albany, OR to expand and refine the Blowout and Spill Occurrence Model (BLOSOM) used to predict where untreated and treated oil will migrate following a spill.

To address challenges presented by the Arctic environment, which varies in wave, wind, and type and coverage of ice, scientists at MSL are developing a new class of herding agents that provides herding and sorbent properties to promote the collection or in situ burning of oil and accelerated bioremediation for oil that escapes treatment. The research draws from capabilities in mesocosm testing and environmental simulation, materials science, and applied biotechnology, including microbiology, molecular biology, and bioremediation.

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