Offshore Structures: The Environmental, Economic and Structural Design Drivers

Abstract

Composite structures are becoming more attractive to the offshore oil industry as weight becomes a critical design criteria in deep waters. Composites’ high strength to weight ratio offers potentially large weight reductions with comparable or enhanced performance for many applications. A team lead by Northrop Grumman Marine Systems (formerly Westinghouse Marine Division) consisting of DeepStar, ABB Vetco Gray, Offshore Technology Research Center, Reading and Bates and Hexcel (formerly Hercules) supported by NIST is currently developing one such offshore application, a composite drilling riser. This paper describes the design drivers for a composite drilling riser capable of operating at a 6000 foot water depth. The design drivers are categorized into three areas: environmental, structural and economic and directly determine the material selection, material property allowables, composite lay-up and composite to metal termination design.