March 20, 2018
Dr. Brun Hilbert, Principal Engineer in Exponent's Mechanical Engineering Group, served as a member of the National Academies of Sciences, Engineering and Medicine Committee on Connector Reliability for Offshore Oil and Natural Gas Operations. The Committee has released to the public its report, published by National Academies Press, "High-Performance Bolting Technology for Offshore Oil and Natural Gas Operations." This report is the second of two major deliverables requested by the sponsor, the Department of the Interior's Bureau of Safety and Environment Enforcement (BSEE).
The first deliverable was a proceedings of a workshop that was held in Washington, D.C., on April 10-11, 2017. The goal of the workshop was to develop an understanding of the outstanding issues (materials, design loads, coatings, corrosion protection, failure prediction and prevention, and quality management), associated with these previous bolt failures and to discuss possible paths for reducing risks associated with bolts used in subsea oil and gas operations. The Committee Report and the Proceedings of the Workshop are available here.
Tremendous oil and gas resources exist in the continental shelf and are becoming accessible with advances in drilling technology. This has sharply increased the number of drilling rigs at work in deep water environments, primarily within the Gulf of Mexico. The large oil spill due to the Deepwater Horizon accident has focused more attention on preventing oil releases into the ocean. In addition to the Deepwater Horizon environmental release, there have been several near misses due to bolt failures over the past 15 years.
Even though in-service fastener failures (bolts and connectors) are rare and have not led to a major release of oil, eliminating or further reducing the possibility of a failure has become a priority for both industry and government. A summary of selected subsea bolt failures is compiled in is included in this report (Appendix E). The emphasis is on those fasteners that hold together critical pieces of safety equipment, particularly blow out preventers (BOP), and those that secure the pressure boundary in risers.