Effectiveness, Environmental Pathways and Operational Readiness of OP-40 Chemical Herder when Used in Conjunction with In-Situ Burning for Oil Spill Response in the Offshore Arctic

Abstract

The Arctic is the northern most part of the Earth, and within Alaska (United States), is home to approximately 10,000 people, the majority of which are indigenous populations. It contains some of the largest reserves of natural resources and the most extensive and continuous wilderness areas in the world. As the Earth’s climate changes, so does the Arctic and its economy, its commercial opportunities as well as the associated risks. One such risk is the unintentional release of oil into the offshore Arctic environment from resource extraction, commercial fishing, tourism or marine shipping. Oil spills in this environment prove damaging to the marine population, as well as logistically challenging given the remote landscape, harsh temperatures, ice cover and difficult working conditions.

The primary oil spill response methods are mechanical recovery, chemical dispersion, and/or in-situ burning. Regarding possible spills in Arctic seawaters, the choice of response option depends on ice cover, along with other factors. In-situ burning is a possible primary response option if the oil slick is thick enough to sustain burning and may be one of the few options available for use in ice-covered waters. Chemical agents, known as thickening agents or “herders”, may enhance the opportunities for in-situ burning by temporarily thickening of the oil slick in order to sustain a burn. With careful evaluation of the physical and chemical processes involved with herder application and subsequent burning and their ultimate fate within the environment; industry, government, Alaska native and other interested parties would be better able to assess the usefulness of this response option and judge the safety and effectiveness of herder use in the Arctic, as well as estimate its effects on the environment.

This research was conducted to aid interested parties in their oil spill response action decision making process. The research plan was designed to assess the effectiveness, environmental pathways and operational readiness of herder assisted in-situ burning in a range of simulated Arctic conditions. Siltech OP-40 chemical herder was used in all three testing trials: laboratory, meso-scale and field tests. The herder was applied to Alaska North Slope (ANS) crude followed by ignition. OP-40 was successful at thickening the oil slick to enable ignition and sustained burning. OP-40 herder was shown to have ease of application in cool weather, and the burn residue was able to be successfully collected following cessation of the burn.

Environmental testing was conducted on the air, water and burn residue pathways. Herder was not detected in the air emission plume tested as part of the field trials. Herder was measured in the water column, accounting for a projected 99% by volume of the applied herder. Herder was measured in the burn residue at the highest concentrations. This dissertation does not address the issue of environmental risk and the net benefit from in-situ burning (ISB) and herders; however, the potential benefit of herder use increases with the burn efficiency and these scale experiments give insight into efficiency and fate.