Description
Increased oil prices have renewed interest in the arctic especially in view of the large potential reserves expected to be found there. In fact, the National Geological Society estimates that approximately one-third of all remaining reserves are expected to be found in the arctic. The legacy of designs for offshore structures in conditions were they have had to contend with ice forces in addition to waves, wind and currents shows that the earliest designs are based on fixed platforms and were deployed in relatively shallow water. These include designs which are based on grounded barges mounted on a prepared seabed section. More recent designs are based ship shaped FPSO’s which have a disconnectable inboard weather vaning turret. Under the threat of ice forces, which the vessel is not designed to withstand, the hull is disconnected from the mooring turret.
During the last decade there have been a number of significant developments in deepwater floater technology increasing the production water depth from about 4,000 ft to 8,000 ft. Designers are now considering ways to adapt this deepwater floater technology to arctic conditions even in situations where the water is not considered, by definition, to be deep water.
The presentation is an overview of design considerations for offshore floaters in the arctic. It discusses how the added environment of ice affects these designs and discusses some engineering solutions.
John Murray has over 25 years’ experience working on offshore structure designs for open water and ice-covered regions. He started his career with the National Research Council Canada in 1985, where he was head of the Ocean Engineering Program, responsible for the Council’s national offshore development program. In 1997, he joined Spars International Inc. in Houston. For the past 12 years, Dr. Murray has worked primarily in concept development for deepwater floaters and riser designs, both as a Principal Engineer with Technip Offshore and since 2006 as Director of Technology Development with FloaTEC, LLC. He holds a PhD in Ocean Engineering, has co-authored over 100 technical papers in journals and conference proceedings, and holds a number of patents. He is a registered professional engineer in Canada and the State of Texas.