Scheduling of Offshore Support Vessels on the Grand Banks

Abstract

The Grand Banks off the coast of Newfoundland and Labrador present a challenging environment for the offshore oil industry. There are currently three oil producing developments, with an average distance offshore of approximately 185 nautical miles. The environment is characterized in winter by strong winds, high waves and the presence of pack ice. In the summer the area is prone to heavy fog and low visibility. Offshore support vessels are a key element of any marine based drilling and production system and they must function effectively in this environment. Their key role is to provide a timely delivery of supplies (and if necessary personnel) to and from the offshore platform. The main challenge for the existing vessels operating on the Grand Banks is that there is a high level of seasonal variation in the weather conditions between winter and summer. The research results presented in this paper were a preliminary attempt to understand the relationships between the distance offshore of the production or drilling platform, the number of supply vessels serving a platform, vessel speed, weather conditions and the required slack in the vessel schedule to provide a reliable service. This analysis was undertaken as there is significant potential for offshore development within the Flemish Pass Basin, which is even further offshore (270 nautical miles) and in a more severe winter wave regime. The results show that although the current Offshore Support Vessel fleet is satisfactory for 185 nautical miles offshore, there will need to be some changes in order to provide effective service when developments move further offshore. This may include a combination of more ships to service an offshore platform, faster ship speeds, reduced frequency of delivery, or increasing the limiting wave height for lifting operations.