The Workshop on Bolting Reliability for Offshore Oil and Natural Gas Operations was held to provide the Committee on Connector Reliability for Offshore Oil and Natural Gas Operations with a deeper understanding of the many issues that can lead to fastener failure. Oil and gas industry representatives, aviation and marine engineers, and government officials shared their expertise and gained insight from others through 17 individual presentations and 4 open discussion sessions.
The workshop was divided into four panels, each focusing on a different aspect of the design, use, criticality, and reliability of fasteners used in subsea oil and gas operations. Panel 1 addressed the design requirements for critical bolts, such as meeting API standards, choosing the right materials, and understanding how bolts interact with the subsea environment. Panel 2 focused on the quality of the bolts, specifically what material is least susceptible to HE, how important manufacturing processes are for reducing risk, the importance of studying and sharing near failures, and how the number of variables increases the challenges of creating and meeting standards. Panel 3 featured industry representatives who discussed in greater depth how subsea bolts’ performance is assessed and how their reliability might be improved. These included BOP successes and failures, how the known and the unknown effects of the environment and CP affect performance, how RCAs can be used to improve reliability, and what standards require of critical fasteners. Panel 4 speakers discussed the development, application, and enforcement of standards and regulations in a range of fields: the Navy, an aviation company, API, and the FAA.
Despite the wide variety of expertise represented and the range of topics discussed, there were several common threads raised throughout the workshop. One area of particular focus, for example, is how to prevent HE, which is thought to be a primary cause of EAC. Three factors—material susceptibility, stress, and environment—combine to cause EAC. Although most participants agreed that all three factors are important, there is room for debate regarding which factors are most important, which factors are already being addressed, and which could be altered further to reduce the overall likelihood of EAC.
Many participants pointed to a need for more research to address uncertainties and pin down the specific material, environmental, and operational factors that contribute to critical bolt failure. For example, it is unclear how changing environmental conditions as drilling goes into deeper and more extreme environments might affect bolt reliability. The impacts of certain manufacturing processes, such as casting, heat treatment, and coating, and operational variables, such as torquing and CP, are also debated.
Participants stressed the value of learning from the experiences and approaches of each other and of other industries. Many participants, for example, pointed to audits and RCAs as excellent tools for identifying problems and making improvements, and to collaboration across industries and with regulators as an important mechanism for translating problems into solutions. Near failures and nonfailures are well worth examining closely, as are supply chains and quality assurance programs, many participants said. In addition, education, training, and certification systems could help reduce the impact of the human factor from the factory floor to installation to maintenance and inspection practices.
The potential negative consequences of fastener failure are clear. Overall, workshop participants discussed how more research, more understanding, and more knowledge sharing could solve this complex problem.
Building on the ideas discussed in the workshop, the committee will next conduct a consensus study to gather additional data and insight. All of the ideas, information, and data will be incorporated into a report that will identify options for mitigating the risk of fastener failure in subsea environments.
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