Advances in Treating Agents for Oil Spill
Response with Applicability to the Arctic
Amy Tidwell & Tim Nedwed, ExxonMobil Upstream Research Company
Ian Buist & Randy Belore, SL Ross Environmental Research, Ltd.
Gerald Canevari, Canevari & Associates
2012 United States-Canada Northern Oil and Gas Research Forum
Anchorage, Alaska
November 13-15, 2012
Outline
• The OSR Toolbox
• Dispersants
− Background
− Development of New Dispersant
• In situ Burning
− Background
− Development of Herding Agents
• Commercialization Plans
• Summary
Spill Response Options: The Toolbox
Mechanical Recovery:
Booms & Skimmers
Monitor &
Evaluate
In-Situ Burning
The goal is to design a response
strategy based on
Net Environmental Benefit Analysis
Dispersants
Background on Dispersants: What are they?
• Dispersants are solutions of surfactants dissolved in a solvent
• Surfactants reduce oil-water interfacial tension – allows slicks to disperse into
very small droplets with minimal wave energy
• Dispersed oil rapidly dilutes to concentrations <10 ppm within minutes, <1
ppm within hours, ppb range within a day
Background on Dispersants: What are they?
• Oil-degrading micro-organisms are present everywhere
• Each dispersed oil droplet is a concentrated food source that is rapidly
colonized and degraded by marine bacteria
• Rapid dilution allows biodegradation to occur without nutrient or oxygen
limitations
• Rapid dilution reduces toxicity issues – dispersed oil plume dilutes to <1 ppm
in hours and <1 ppb within 1 – 2 days
Graphic consistent with Venosa & Holder, EPA 2007
Development of New Dispersant Gel
• Consistency of warm honey
• Positively buoyant drops
• Cohesive & persistent
• Oleophilic behavior
• 85+% active ingredient
9500 Pour Video
Gel Pour Video
Properties of Dispersants Used in Testing
Dispersant Viscosity (15C)
Viscosity
(cP)
Shear Rate (s-1)
Density @ 20C
(g/cc)
Corexit 9500
107
100
0.968
New dispersant
1500
10
0.921
Dispersant
Development of New Dispersant: Testing
Dispersant-effectiveness results for light, medium, & heavy crude oils
Background on in situ Burning
• Controlled burning of oil “in situ”
• Conventional process requires booms to keep oil thick
• Fire resistant booms are a challenge to transport
• Only operational use offshore during Deepwater Horizon
Newfoundland Offshore Burn Experiment, 1993
Background on in situ Burning: Herding Agents
• Herders enable in situ burning without booms
• Requires application of small volume of surfactant on water surface on
perimeter of slick
• Herding process requires minutes to thicken slick enough to burn
• Herder application and burn initiated quickly from a single helicopter
Lab-scale application of herders
Development of Herders: Recent Testing
• Herder testing since 2004 focused on supporting in situ burning in ice
• Recent field tests were done in very limited ice supporting use of
herders in open water
Field testing of herding agents, 2008
Commercialization Efforts:
New Dispersant and Herders
• Dispersant gel
− Plans are for dispersant gel to be available for sale by early
2013
• Herding agents
− Currently listed with US EPA for potential use in US marine
waters
− Commercially available through Applied Fabrics, Buffalo, New
York
− Helicopter delivery system under final development
Summary and Conclusions
• Two new treating agent technologies – new dispersant and
herding agents – have been developed which could enhance oil
spill response capabilities
• New dispersant
− Treated light-to-medium oils with 2/3 less dispersant than a
currently available product
− Dispersed viscous oils that were previously considered undispersible
• Herding Agents
− Potential to enable in situ burning in both ice conditions and
open water without the need for fire-resistant booms
− May turn an infrequently used response option into a readily
available tool because it can be applied rapidly from helicopters
Slide 13
Questions
Background on Dispersants
Dispersants Enhance Removal of Oil from the
Environment Through Biodegradation