Composite systems are a generally-accepted method for repairing corroded and mechanically-damaged onshore pipelines. The pipeline industry has arrived at this point after more than 15 years of research and investigation. Because the primary method of loading for onshore pipelines is in the circumferential direction due to internal pressure, most composite systems have been designed and developed to provide hoop strength reinforcement. On the other hand, offshore pipes (especially risers), unlike onshore pipelines, can experience significant tension and bending loads. As a result, there is a need to evaluate the current state of the art in terms of assessing the use of composite materials in repairing offshore pipelines and risers.
The paper presents findings conducted as part of a joint industry effort involving the Minerals Management Service, the Offshore Technology Research Center at Texas A&M University, Stress Engineering Services, Inc., and four composite repair manufacturers to evaluate the state of the art using full-scale testing methods. Loads typical for offshore risers were used in the test program that integrated internal pressure, tension, and bending loads. This program is the first of its kind and likely to contribute significantly to the future of offshore riser repairs. The end result of this study was the development of a carbon-fiber repair system that can be easily deployed to provide significant reinforcement for repairing risers. It is anticipated that the findings of this program will foster the future.
Alexander, C., “Design of an Optimized Composite Repair System for Offshore Risers Using Integrated Analysis and Testing Techniques,” 2012 Offshore Technology Conference, April 3 - May 3, 2012, Houston, Texas.