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January 2011 www.sname.org/sname/mt THE COMPLEXITY OF AN OIL SPILL in ice is usually greater than a similar spill in open water. is represents a chal- lenge in predicting the fate and behavior of an oil spill in comparison to open water conditions. In 2006, a Joint Industry Project (JIP) was begun to study oil spill cleanup in ice and improve spill response operations in arctic waters. Coordinated by SINTEF Materials and Chemistry in Norway, participant companies in the JIP included Agip KCO, Chevron, ConocoPhillips, Shell, Statoil, Total, and the Norwegian Research Council. ere were a total of nine projects in the JIP, and the R&D piece included two large-scale eld experiments carried out in the Norwegian part of the Barents Sea east of Svalbard. See the sidebar article, Industry Collaboration,? for more information on the JIP and the response techniques that were evaluated during the program. e JIP focused on the large quantities of oil that are usually assembled in leads between the ice oes. e main objective of this part of the program was to generate new knowledge on the behavior of oil spills in ice for a broad range of oil types. Five dierent crude oils were selected for laboratory, basin, and eld weathering experiments. e selected oils represent dif- ferent groups of oil types and span a large variation in oil properties. e results from these studies form a representative data set that can be used to calibrate the weather- ing model. As a part of the laboratory test program, a large number of weathering experiments with dierent ice conditions (open water as well as 30, 50, 70, and 90% ice coverage) were carried out at SINTEFs experimental basins in Trondheim. To verify the main trends from the laboratory testing, several eld experi- ments were performed in the Barents Sea in May 2009. At that time, 7 m 3 of fresh crude oil were released uncontained between the ice oes to study oil weath- ering and spreading in ice. e results showed that the water uptake from the field experiment matched the water uptake from the basin experiment with corresponding ice coverage. The rate of the weathering process is reduced when oil is spilled in ice compared to a spill in open water. is is due mainly to reduced energy input. is has impor- tant operational consequences related to the window of opportunity for the use of various oil spill response techniques, especially in- situ burning (ISB) and use of dispersants. is extensive data describing weath- ering processes of an oil spill in ice as a function of oil composition and ice con- ditions were used to improve existing algorithms describing oil weathering in ice. ese algorithms have been implemented into the SINTEF Oil Weathering Model. ese new capabilities are valuable for oil spill contingency planning, tabletop train- ing, and real response operations. ISB of oil spills in ice ISB is one of the response techniques with the highest potential for the removal of oil spills in arctic conditions, especially in snow and dense ice. ISB is well proven and established as part of oil spill contingency planning in many arctic areas. Its eectiveness is veri- ed by previous lab and eld studies in the U.S., Canada, and Norway, showing removal eciencies of more than 90%. The suitability of ISB depends on the initial oil characteristics and the weath- ering state of the oil. Factors such as slick thickness, oil weathering (particularly emulsication and content of volatile com- ponents), igniter temperature, swell/waves, and wind conditions are important for a successful burning. e main focus in this part of the program has been to study the ignitability of an oil spill as a function of oil properties and the degree of weathering, and to establish algorithms that enable the prediction of the window of opportunity for using ISB. e second part of the project has tested whether ISB can be improved by the use of chemical herders to help increase lm thickness and by the use of re-resis- tant booms in partially ice-covered water. Ignitability, oil type, and weathering. e laboratory measurements of ignitability were performed with a laboratory burning cell developed as the rst part of the oil in ice JIP. is testing of ignitability as a function of weathering was performed on oil samples articially weathered in the laboratory. To ensure the validity of the extensive data set generated with the laboratory cell, two experimental oil releases were per- formed during the 2009 large-scale eld experiment. In the experiment, 2 m 3 of crude were released uncontained between the ice oes, weathered for six hours, and then ignited. e total burn time was 26 minutes and the burn eciency was esti- mated to be approximate 90%. Ignitability was also measured for a larger 7 m 3 exper- imental oil release and this slick was