Herder Burner: Aerial Operations for Oil Spill Response

In April 2015, ACUASI, in partnership with University of Alaska Fairbanks scientists, conducted field tests of aerial operations for Arctic oil spill response at Poker Flat Research Range, near Fairbanks Alaska.  There, scientists released Alaska North Slope (ANS) crude oil in a manmade water basin and used a herding agent to increase the thickness of the oil for ignition. The oil was ignited from above using unmanned aircraft systems and helicopters. The series of test burns were part of a team effort between University of Alaska Fairbanks scientists and researcher partners supported by the International Oil and Gas Producers Association aimed at improving understanding of how herding agents can be used to mitigate oil spills.  ACUASI participated by applying herder and igniting the oil from the air with UAVs; both the Ptarmigan and Responder unmanned aircraft were deployed for this mission.

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The project’s overall objectives were to:  1) prove the operational feasibility of an aerial herder/burn response strategy using manned and/or remote-controlled helicopters; 2) reaffirm the effectiveness of herders in open water and with ice present, 3) validate a rapid response aerial system that could enhance responders’ ability to use offshore burns in drift ice conditions and ice-free waters.  Burn efficiency was measured to affirm these methods as viable oil spill response protocols.

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Controlled in-situ burning (ISB) of an oil slick as a response technology has been researched and employed in one form or another at a variety of oil spills since the late 1950s, including limited use during the Exxon Valdez accident and more extensive use during the Deepwater Horizon incident.  ISB is an oil spill response option particularly suited to remote, ice-covered waters.

Thick oil slicks are the key to effective ISB and if ice concentrations are high, the ice can limit oil spreading and keep slicks thick enough to burn. However, in drift ice conditions and open water, oil spills can rapidly spread to become too thin to ignite. Fire-resistant booms can collect and keep slicks thick in open water; however, even light ice conditions make using booms challenging.

Researchers have studied the use of herding agents in oil spill response since the 1970s. Extensive laboratory and field research over the past ten years has focused on the use of herders as an aid to ISB operations, primarily in open drift ice or calmer open water conditions.

The mission was very successful in that the unmanned aircraft systems proved to be an excellent tool for fast deployment of this oil spill response approach. With aerial application of both the herding agent and igniter, the herder/burn combination becomes an extremely rapid and effective new response tool, independent from vessel support, and without putting humans on the ice. The slower weathering of oil slicks in ice and cold water can also extend the window of opportunity for this new tool.