Risk Analysis for Arctic Offshore Operations

Abstract

The ice conditions in the Beaufort Sea are very variable, particularly in the deeper water regions. This variability greatly influences the probability of success or failure of an offshore operation. For example, a summer exploratory program conducted from a floating drilling unit may require a period of 60 to 100 days on station. The success of such a program depends on:the time when the winter ice conditions deteriorate sufficiently for the drilling unit to move on station;the number of summer invasions by the arctic ice pack, forcing the drilling unit to abandon station;the rate at which first-year ice grows to the ice thickness limit of the supporting icebreakers; andthe extent of arctic pack expansion during the fall and early winter. In general, the ice conditions are so variable that, even with good planning, the chance of failure of an offshore operation will not be negligible. Contingency planning for such events is therefore necessary. This paper presents a risk analysis procedure which can greatly benefit the planning of an offshore operation. A floating drilling program and a towing and installation operation for a fixed structure are considered to illustrate the procedure.