Ice Management To Support The Kulluk Drilling Vessel

Abstract

OFFSHORE PRODUCTION Ice management to support the Kulluk drilling vessel J. HNATIUK and B.D. WRIGHT Gulf Canada Resources Inc. ABSTRACT A second-generation drilling vessel has been constructed to extend the drilling season in the Beaufort Sea through the use of a unique hull design, moori.ng system and icebreaking support vessels. The unique designs of the drilling vessel, icebreakers and supply boats are described. The Kulluk vessel, designed to drill in open water or newly-formed ice, commenced drilling in August 1983. It was soon called on to cope with the most severe ice conditions in nine years. The ice surveillance and ice management procedures employed in coping with the prematurely severe 1983 ice conditions arepresented. Depending on the severity of the ice hazards colour code alerts were triggered which dictated the nature of the drilling operations permissible.A pre-requisite for operations is a knowledge of which icefeatures present a hazard to the drilling vessel-opera-tionally, the hazards must be detected using radar and visual reconnaissance from aircraft or vessels. Predictions of the veh)city, trajectory and time of arrival of the hazardous features are made based on plots of radar and other information. Action is taken to mitigate the hazards through the use of the four powerful icebreakers and supply bo,ts, biased tensioning of the mooring system, disconnecting the riser or, in the extreme event, moving from the location. The icebreaking vessels work at assigned dis-tances from the drilling unit to either break floes and pressure ridges into less hazardousfeatures or to deflect thefloes away from a collision course. The ice management system for the Kulluk was put to a severe test in its first year of Keywords: Kulluk drilling vessel, Beaufort Sea, Mobile arctic caisson, Retained islands, Icebreaking support vessels. operation but it performed admirably well. Introduction The continental shelf of the Beaufort Sea has long been considered to have the _ potential for major oil and gas accumula-tions. During the period 1963 to 1969, offshore permits to explore for oil and gas were issued for the majority of the shelf which extends some 125 km to 175 km from shore to water depths of 200 m. The Geological Survey of Canada's aver-age expectations of the hydrocarbon potential of the Beaufort Sea -Mackenzie Delta area are 1347 million M3 of oil and 1865 billion M3 of gas(l). Numerous encouraging hydrocarbon discoveries have been made in the Beaufort Sea since offshore drilling commenced in 1973. The commerciality of reserves will depend on many factors such as pay thickness and other reservoir character-istics, well productivities, i,eservoir depth, water depth, distance from shore, environmental forces, sea bottom condi-tions, capital and operating costs, crude oil prices and the fiscal regime.Sea ice conditions in the Beaufort Sea are such that the drilling season from conventional ice reinforced drillships is -only 3 to 4 months. The second-genera-tion drilling vessel, BeauDril's Kulluk, was constr...

Real-Time Pack Ice Monitoring Systems - Identification of Hazardous Sea Ice Using Upward Looking Sonars for Tactical Support of Offshore Oil and Gas Projects

“…Offshore oil and gas activities in ice infested waters are being considered at a much expanded level for the present decade than past decades, with ambitious new plans being developed to move exploration activities into deeper waters with more severe ice conditions. Ice management systems for stationary vessel operations in moving pack ice is built on experience dating back to the late 1970's in the Canadian Arctic (1,2) and off the Canadian East Coast (3). As noted by Keinonen and Martin (2), the early ice management systems were experimental, an approach which is no longer acceptable given higher safety and environmental standards.…”

“…Past tactical sea ice information systems, used in support of ice management for stationary vessel operations, relied heavily on information sources including: visual and marine radar detection of sea-ice from the stationary vessel and its support vessels; satellite (radar and radiometric) surveillance; and manual predictive systems of identified hazardous ice features. Examples of earlier ice information systems to support ice management are provided in references (1) and (3).…”