Flexible Fiber-reinforced Pipe for 10,000-foot Water Depths: Performance Assessments and Future Challenges

摘要

The primary aim of the present composite development program is to enhance access to deepwater fieldsin the Gulf of Mexico, Brazil, and West Africa. To accomplish that goal, composite materials are beingincorporated in unbonded flexible pipelines to lower mass and enhance the overall system performanceto expand the operational design envelope. In addition, the use of composite materials will allow asignificant improvement in pipe operating pressure (>70 MPa), pipe operating temperature (>125C) anddue to increased CO_2 and H_2S resistance, will improve sour service performance and lifespan.Composite materials are well known for their low density and high specific strength, stiffness andfatigue performance. These properties are desirable and will certainly enhance pipe performance, but theoverall performance of the pipe during all stages of manufacture and deployment must be considered, aswell as a conservative approach to introducing these new materials. Some of the key factors that need tobe assessed are material failure modes under varied pipe loadings, dynamic interactions and exposure tosevere oil field environments. There are several individual standards, specifications and joint industryprojects (JIPs) focused on composite pipes that address some of these issues, but there is also a generallack of consensus with regard to testing standards and understanding of the long-term performance. Asflexible pipe suppliers, the industry must aim to provide performance assessments and address all keychallenges to allow the flexible pipe industry to build confidence in the new and enabling composite pipetechnologies.In a previous paper, we presented design concepts and a toolbox approach to construct differentcomposite pipe solutions to meet all the aforementioned performance parameters. The present paperselectively highlights important failure modes and design considerations, demonstrates an understandingof behavior in the matrix and fiber phases, and addresses concerns related to the chemical performanceof composite materials. The present paper also highlights and addresses some of the concerns ofcomposite pipes and focuses on areas for future development and testing. These results will help supportthe selection and standardization of analysis tools and testing methods across the industry. Bespoke testingcapabilities to address the relevant failure mechanisms and installation strategies for composite pipes willalso be discussed.