The following provides an overview of the April 20th, 2010 oil rig fire, sinking and oil spill in the Gulf of Mexico: what went wrong and limitations of spill response. The discussion is addresses Canadian limitations in alternative spill response technologies - in situ oil burning and dispersant use.
A black-eye and reality check for the offshore oil exploration and production industry when the Deepwater Horizon drilling rig caught fire on April 20th, burned, then sank in the Gulf of Mexico a few days later. Transocean’s drilling rig represented the cutting edge of deep-water drilling technology. The Deepwater Horizon is a floating rig that relies on thrusters to stay in place, rather than mooring lines. It had just finished cementing casing to prepare the site for oil production; with pipe lengths of about 1,500 meters (5000 feet) underwater and then another 4,000 meters (13,000 feet) under the seabed.
Oil companies have pushed further offshore in search of oil, as older, easier oilfields dry up and foreign governments cut access to reserves. The emphasis on deepwater exploration has led to a surge in construction of rigs capable of drilling in such depths. It is this cutting edge engineering and intensive drive for oil that puts both workers and the environment at risk from serious mishaps. The numerous “fail safe” safety systems to prevent well blow-outs didn’t work for the Deepwater Horizon. As with new technology and engineering designs that are largely based on computer modeling, there can be a lack of real-situation testing and experience to provide proof-of-concept - let alone trained operators.
As for the emergency response to this incident, good emergency management would specify several response objectives; they would in turn be vetted to ensure they didn’t conflict and are achievable. In the case of the Deepwater Horizon, it was clear that the first objective was to rescue workers and search for the missing ones. As for the rig itself, putting the fire out with extensive use of firefighting vessels was flawed for several reasons. First, loading the rig with water precipitated its sinking. Second, the water deluge of the oil laden rig significantly contributed to marine pollution. Once an industrial site is fully engulfed by fire and there are no exposure to people and property, its often prudent just to let the structure burn rather the generate water/toxic mixtures. This strategy is often difficult for fire fighters to comprehend.
After the rig sank and the oil slick persisted, the next response step taken was to burn the oil burn in place (in-situ) anyways. In-situ oil burning is a very effective response tool for offshore oil spill mitigation as it can rapidly remove over 90 per cent of the oil with minimal impact to regional air quality. Generally such controlled burning is done by corralling the oil behind specialized fire boom and igniting it. Canada does not have an in-situ oil burning decision policy or guideline, though Environment Canada was very much leader in the science and human health aspects of this alternative technology to mechanical booming and skimming.
The high winds and waves over the course of the spill has hampered on-water oil recover by mechanical methods of skimming and booming. Don’t be fooled, even under the best conditions the most one can expect is 15% of any oil to be recovered by this technology. The adverse seas In the Gulf of Mexico would make one optimist to achieve anything over 5% recovery of either fresh or emulsified oil. The vast portion of the oiled area is of sheen thickness. Oily sheens are not recoverable, as they are at the molecular level of thickness - hence their rainbow appearance. One would need to boom and sweep hectares of water to recover a few liters of sheen. When the media states... “crews have retrieved about 1,052 barrels of oily water” - you can guarantee that it is mostly water in the containers.
But alas, there is another solution being used for the Deepwater Horizon incident where rough water is actually advantageous. It is the use of dispersants that is sprayed over the oil slick by specially equipped aircraft and vessels. Though dispersants get a bad-rap by environmentalists, they are very effective in achieving a net environmental benefit. A net environmental benefit (NEB) is where there is some ecological impact, but over all there is more advantages than disadvantages. NEB is not based on economics; that is a cheap solution. New dispersant formulations have low toxicity to marine organisms. Dispersants help breakup the oil into small particles that enhance biological degradation and photo oxidation. Water agitation by wave helps here. These natural process eventually degrade the oil to its basic constituents - carbon dioxide and water. The majority of nations use dispersants as a primary response tool to be used on conjunction with mechanical methods - but not Canada.
Both in-situ oil burning and dispersants have been talked about in Canada for over 20 years, but again no government commitment to approve their use. Consequently, there is no incentive for industry to spend money to buy and train on these methods. Dispersants and in-situ oil burning are not part of the shipping and oil handling industries preparedness requirements under Canada’s current Response Organization regime for oil spills. They essentially are the only meaningful tools for offshore oil spill response on the West Coast.
So the oil is going to reach landfall along four US states that share the waters of the Gulf of Mexico. What are the response options now? Nearshore protection booming can be effective, but generally they will be misplaced. Protection booms are often deployed more for show than function. This leaves the Gulf’s shores and mangroves marshes vulnerable to oiling. When mangroves are oiled, they are best left alone for natural cleaning. This is because oil only has two basic impacts: smothering and toxicity. Shoreline cleanup operations adds trampling, entrenching, and crushing of shoreline sediments and organisms. It is poorly understood that effective oil removal from shores and vegetation does not necessarily equate to a good job. The objective of shoreline cleanup is to do no more harm, and if undertaking treatment, to achieve a net environmental benefit. Many lessons have been learned from such spills as the Exxon Valdez tanker incident on what not to do. You can expect to see shoreline cleanup in the US States as a political imperative to show something is being done, but the environment may not actually benefit.
The environment is generally more resilient to spilled oil compared to torn social-fabric of coastal communities caused by uncertainty for their future enjoyment or commercial use of affected marine environment, poor government and industry communication on response efforts and what objectives are being considered, and inappropriate allocation of response resources. The reality check for the offshore industry by the Deepwater Horizon incident will be how poor oil spill response will be due to limited options to recover oil based on the working environment and limitations of response equipment. The black-eye will be how much politicians and the public will be watching over them as emotions are even harder to mitigate.