Summary
Objective
As water depths increase, there is growing interest in the use of composite production risers instead of steel risers for deepwater production systems. The MMS’s Deepwater Operating Plan (DWOP) requires that new technology introduced in a deepwater development project must be shown to be as safe as existing technology. The project will compare the risks of a composite production riser for deepwater floating production systems with the risks of a steel riser that has the same functional requirements and service life, to demonstrate the safety of a composite riser relative to a steel riser.
Approach
A Comparative Risk Analysis (CRA) will be conducted to compare the risks of composite and steel production risers. The specific riser functional requirements, service life, and configuration(s) for the composite riser will be based upon results from DeepStar Project 6120 on permitting composite risers, and will be subject to MMS approval. A configuration for a steel riser with the same functional and service requirements will be developed, and both will be designed in sufficient detail for analysis.
The Study Team will include expertise in the areas of risk analysis, deepwater production riser configuration and design, composite riser analysis, and steel riser analysis. The Study Team will interact with experts from industry, class societies, and regulatory authorities through a series of Workshops to (1) develop the riser systems for the CRA; (2) determine appropriate risk measures for this study; (3) identify hazards for the composite and steel riser, and the resulting consequences of failure; and (4) estimate the frequencies of such events.
The Study Team will use this information to estimate the risks for the composite and steel riser systems. Each riser system will be quantitatively analyzed to determine its responses to hazards and the resulting risks. Existing data will be sought to support the analyses. The resulting risks for the two riser systems will be compared to determine the risks of the composite riser relative to the steel riser. The study will be conducted such that the larger contributors to risk can be identified so that appropriate risk mitigation strategies and measures can be studied.
The Study Team will review intermediate results with the industry, class society, and regulatory experts at appropriate milestones to get their advice and input as the study progresses.
Deployment of Results
Results from this CRA study will be shared with the Workshop Participants as part of the study process, and will be documented in a Final Report that will be available to the MMS, other regulatory authorities, Workshop Participants, and the public. Results from this study could also provide a basis for
- Developing a process to qualify other new production or drilling risers,
- Developing any needed certification or testing requirements for composite risers
- Identifying NDE methods that could be useful in sensing the ongoing performance of composite risers during field service
Related Publications
Structural Response of Composite Production Risers (2005), W. K. Kim, O. O. Ochoa, E. G. Ward, & C. A. Miller, paper at Fourth International Conference On Composite Materials for Offshore Operations, Houston, TX, October 4-6, 2005.
Ochoa, O. O., and Salama, M., “Offshore Composites: Transition Barriers To An Enabling Technology”, International Journal of Composite Science and Technology, 65, pp. 2588-2596, 2005.
Kim, W., Ochoa, O. O. and Miller, C. A., “Axial and Burst Analysis of Offshore Composite Risers,” Proceedings of the American Society for Composites, Philadelphia, PA, September 7-9, 2005.
