Application of Composite Materials in Deep Water Offshore Platforms

Abstract

Abstract This paper presents the results of a joint project between Conoco Inc., DuPont Advanced Materials System and Kvaerner to investigate the technical feasibility and cost benefits that may be derived from the use of composite materials for structural applications in deep water platforms. The focus of the study was a hypothetical Tension Leg Wellhead Platform (TLWP) installed in I, 400 m water depth in a typical North Sea environment. Although a TLP r e p m t s the most weight sensitive platform configuration, almost all floating production facilities will some benefit from saving weight and lower maintenance costs associated with composite materials. The project started with the premise that all the platform structure would be considered for composites applications including the hull, deck, topside facilities, risers and tethers. Further screening m w e d down the emphasis for the preliminary design effort to the hull and deck, although all potential applications were considered in the economic assessment. The design concepts developed were driven by the cost of raw materials and the availability of low-cost large-structure fabrication processes. Global design was performed for a base case steel platform as we1 I as for several alternative configurations each comprising a different degree of application of composites in the topsides, hull and risers. The applications ranged from substituting steel payload with composite alternatives all the way to composite columns and deck pontoons and main structural members. A cost estimate for the different platform configurations was conducted and compared to base case steel TLWP. The paper also highlights important obstacles that need to be overcome before there is wide acceptance of composite materials as a substitute for steel in the offshore industry. Demonstration of the performance of composites is particularly critical for primary structural applications such as those considered in this study. Introduction In June 1995 was established between DuPont, Conoco and Kvaerner with the ultimate goal of commercialization of am composite applications within the oil and gas industry. The present study was conducted to investigate the offshore use of composites from a holistic view point in order to provide guidance to themembers as to which particular applications should be pursued Composites have proven to be cost effective and are already being used in a variety of offshore applications such as gratings, being used in a variety of offshore applications such as gratings, skids, tanks, -etc. The objective of this study was to determine if quantum breakthroughs could be made by the use of composites in the primary structure.