Time is the most critical factor when dealing with an Arctic oil spill, says Steve Potter, principal consultant, SL Ross. Small spills can usually be handled by onsite personnel with rig- or platform-based boats and booms. Larger spills require more resources, so land-based or pre-positioned equipment is critical to any response.
In the Arctic, remote locations and limited resources hinder a rapid response as does the cold environment. API Bulletin D16: Suggested Procedure for Development of a Spill Prevention Control and Countermeasure Plan (2010) recommends a tiered responsive:
The key separator is the time needed to activate and move equipment into position to address the spill.
There are three main strategies to manage spills: containment and recovery using vessels of opportunity towing booms and skimmers; in situ burning using vessels towing fire-resistant booms coupled with ignition of the gathered oil; and dispersants for widely spreading or high-volume spills.
Containment and Recovery
Containment and recovery is the preferred approach, but is limited by the available equipment. A large area must be covered in a short time. In a large spill this strategy may only be able to address 1-2% of the total spill area. It is also problematic in open water and shoulder seasons due to the presence of ice.
Even traces of ice limit the effectiveness of containment and recovery. Skimmers need to be able to process ice and have rotating brushes for cleaning closely packed ice. Smaller, single-sweep, oleophilic skimmers work well in more open waters, are more maneuverable, and minimize water pickup.
Containment and recovery is the least effective technique with only 0-30% of the slick recovered.
In-situ burning is best for open water and where there is concentrated ice. It is highly effective with low equipment and manpower requirements. It can reduce slick thickness with 90% effectiveness, and can achieve a burn in thick ice with melt pools at the surface. However, it does involve an environmental tradeoff, since the consuming fire will send smoke and partially burned hydrocarbons into the air.
Dispersant application is an open water technique that can be used with some ice concentrations. It chemically breaks the slick into small droplets, diluting and dissolving the slick into the seawater, so that naturally occurring, oil-consuming bacteria can neutralize the oil. Dispersant effectiveness is dependent on the spilled oil’s properties.
This technique requires minimal equipment and manpower, since dispersants can be applied by air in a short time. The environmental tradeoff is protecting surface resources (birds, sea mammals) versus subsurface resources (fish). As the oil is broken into minute droplets by dispersant and diluted by seawater, its toxicity rapidly drops to low levels.
Of the three techniques, in-situ burning is the most effective, removing 70-90% of the spilled oil. Next are dispersants, with 30-70% effectiveness. Containment and recovery is the least effective at 0-30% recovery.
Equipment delivery, personnel support. and waste handling must be considered and plans developed to address an oil spill. In addition, it is best to get pre-approvals for use of burning or dispersants, since regulations are unclear or non-existent in many arctic jurisdictions.
The industry is well aware of the need for additional Arctic technology development to address oil spills in the high latitudes. There is a need for of new chemistries, equipment and experimental spills to test their effectiveness.
To meet this need, the Arctic Response Technology Joint Industry Project was formed and has developed a series of projects to investigate key problems.
According to Joe Mullin, JIP program manager, there are nine projects underway investigating:
The JIP also wants to create opportunities for field research with other groups, to test their results.