Abstract
The primary aim of the present development program is to enhance access to deepwater fields in the Gulf of Mexico, Brazil, and West Africa by reducing system, transportation and installation costs for flexible production pipe technology. To accomplish that goal composite materials are being incorporated in hybrid unbonded flexible pipe structures to enhance their overall system performance and expand the operational design envelope. The use of composite materials enables significant improvements in operating pressures at larger pipe diameters, reduced weight and top tension, and the enhanced resistance to CO2 and H2S drives further improvements in the structural sour service performance and lifespan.
GE Global Research and GE Oil & Gas, with the support of Research Partnership to Secure Energy for America (RPSEA), embarked on a development program to qualify flexible pipe with an internal diameter of greater than seven inches for ultra-deepwater applications. The concept consists of an optimally engineered combination of metallic and composite reinforcing layer technologies. This hybrid design approach allows the pipe system properties to be tailored to yield the optimal result for any application conditions. The approach offers performance advantages including reduced risk on critical end fitting technology, continuous reinforcement of the liner eliminating discontinuities and local strains by fusing together the reinforcement and liner, superior matrix chemical resistance by using industry proven thermoplastic materials, and a reduced layer count leading to easier inspection.
This paper will provide an overview of the progress made during the collaborative RPSEA program and specifically, will highlight the bespoke testing capabilities developed for the new composite pipe layer. Although there are several individual standards, specifications and Joint Industry Projects (JIP) in relation to composite pipes that address some of the required tests, there remains a general lack of consensus with regard to specific testing standards and understanding of the long term performance, especially considering the variety of composite pipe technologies being developed by the industry. This paper will highlight the results from mid-scale burst testing along with analysis validation, and a bespoke rotating bending fatigue test rig used to assess the bending fatigue of the composite pipe structure. Lastly, progress toward the use of sub-scale tests allied with analysis to more rapidly assess the fatigue life will be discussed.