ARKTOS Shear Zone Evacuation Craft Design Development

Abstract

Abstract The ARKTOS Evacuation Craft has been the primary means of emergency evacuation on Arctic and Caspian Sea bottom founded oil exploration and production facilities for over 20 years. Oil production strategies are currently being developed by major oil companies beyond the Beaufort Sea Shear Zone, where the polar pack and landfast ice meet. The Shear Zone is formed by the moving polar ice pack shearing against the inshore ice that is held fast to the coastal seabed and the shore. Large, irregular ice features can be formed as a result of the shearing action as well as open leads with vertical ice freeboards. A major area of concern for any development within and beyond the Shear Zone is Escape, Evacuation, and Rescue (EER) capability, due to the extreme environmental conditions that will be encountered. In response to a major oil company initiative, a conceptual design for a 75 person ARKTOS Amphibious Evacuation Craft suitable for operation in this region has been developed. This paper describes continuing development of the ARKTOS Shear Zone Craft design, including the affect on performance in ice of increased Craft track width, extended track carriages, increased water jet thrust and hydrostatic drives in combination with inching mode. Also covered are self-righting capability and davit launching from a production platform onto ice or into open water. Introduction Existing offshore oil developments on the North Slope of Alaska are situated on natural or manmade gravel islands that are located within the Landfast Ice Zone. The Landfast Ice Zone extends between the coastline and the barrier islands and up to a few thousand feet beyond. ARKTOS Craft have been used for crew evacuation on all of these installations to date and are typically parked near the edge of the islands, and should an evacuation be necessary, are simply driven away from the island over the land-fast ice, through open water or broken ice/water mixture (Figure 1). With the push to explore and develop Beaufort Sea oilfields further offshore within the Shear Zone and the Pack Ice Zone, gravity based or large floating offshore structures will be required. Personnel evacuation systems for these structures will face even more extreme conditions than the evacuation craft on existing U.S. Beaufort Sea offshore structures such as heavier sea states and mobile ice floes with substantial ice features.