Reducing the cost of protecting arctic marine pipelines against ice gouging

Abstract

The Arctic seabed in shallow water is repeatedly deeply gouged by drifting ice. If the force that the ice applies to the seabed were transmitted to a pipeline, it would almost inevitably create severe damage. The conventional approach to the design problem is to estimate the extreme maximum gouging depth, add the estimated extent of subgouge deformation, add a safety margin, and require that the pipeline be trenched to that depth. The result is to make the trench very deep and very expensive, and to increase the risk of delay and dispute. This paper explores different ways of reducing the cost of protection, among them the choice of route, combinations of horizontal drilling and conventional construction, and protecting the pipeline in situ. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).