An effective Structural Integrity Management (SIM) program allows operators to manage structural risks and reduce the need for hazardous and costly underwater interventions. Inspection and operating decisions and costs are significantly affected by the SIM program definition and execution. This is particularly true for unique, deepwater assets like the Baldpate compliant tower, which features an innovative structural system and is among the tallest structures ever built. This valuable deepwater asset requires a well-executed SIM program to provide confidence that continued service and potentially expanded operations can be safely achieved. Earlier studies had shown that fatigue sensitivities at critical locations could potentially limit Baldpate's useful life beyond the original 20 year target. In order to better understand the characteristics of this unique structure, a series of reassessment analyses were performed. These showed that fatigue sensitivities are not limiting factors for continued service of Baldpate, and the areas of fatigue sensitivity were incorporated into a long term SIM plan to focus future inspections and monitoring efforts. This paper provides details on the challenges facing the execution of the SIM plan, including benchmarking and verification performed for the Baldpate structure using field measurements, implementation of a real-time monitoring system, and targeted underwater inspections. The dynamic behavior of axial tube guides, modeled using gap elements and surface friction, was identified as one of the more critical objectives to be addressed in the SIM plan. This posed a challenge since previous design and assessment efforts did not consider these components critical for global response. SIM options for these components were included in the plan, such as underwater inspections and on-site dynamic motion recording to examine the potentially undesirable behavior of these components. Undertaking these tasks led to affirmation of the structural reassessment results and facilitated development of new SIM resources. In particular, benchmarking the monitoring system provided Baldpate with constant surveillance of its condition. This real-time monitoring plan measures the dynamic characteristics of the tower under different load conditions to indicate when certain unique structural characteristics (e.g., axial tube motion within the guides) would affect the fatigue life of critical joints in the Baldpate tower.

A Structural Integrity Management (SIM) program plays a substantial role in managing structural risks and reducing expensive deepwater in-situ repairs. Inspection and operating decisions and costs are significantly affected by what is defined in a SIM program. Baldpate compliant tower in particular features an innovative structural system and is among the tallest structures ever built. It is a valuable deepwater asset that needs a SIM program backed by a strong technical foundation to provide confidence that continued service and potentially expanded operations can be safely achieved. Earlier studies had shown that fatigue sensitivities at critical locations could potentially limit Baldpate's useful life beyond the original 20 year target. This was mainly due to the conservatism inherent in the spectral fatigue approach which did not capture the innovative and highly dynamic features of the Baldpate tower. In order to better understand the dynamic characteristics of this unique structure and accurately model the tower, a field measurement campaign using 3D accelerometers was carried out. The measurements were then used to benchmark and adjust the computer model. A time-domain rainflow fatigue analysis was utilized to capture the compliant response of the tower for both fatigue seastates and three large storms which have affected Baldpate. This showed that fatigue sensitivities are not limiting factors for continued service of Baldpate, and the areas of fatigue sensitivity were incorporated into a long term SIM plan to focus future inspection and monitoring efforts. This paper provides details on the study performed for the Baldpate structure using field measurement, a rainflow simulation and its contribution to the development of a long term, risk based SIM plan. The behaviors of several unique structural components, such as stress concentration factors at atypical connections, gap behavior and friction lock-up at the guided axial tubes, were also considered. SIM options for these unique structural components are discussed, including underwater inspection methods and on-site dynamic motion recording. These efforts resulted not only in a more promising range of fatigue lives than previously calculated, but also identified areas of focus in support of a risk based SIM and associated inspection plan to support continued service through the asset's viable economic life. This approach is enhanced by a real-time monitoring plan to measure the dynamic characteristics of the tower under different load conditions to indicate when certain unique structural characteristics (e.g., axial tube motion within the guides) would affect the fatigue life of critical joints in the Baldpate tower.

When an aging oil tanker is converted into a floating production facility, unexpected challenges may arise when designing, installing, and maintaining topside process facilities.The oil and gas and marine industries have differing design practices, design codes, quality standards, and maintenance philosophies. These differences can result in underlying integrity issues for which there is little significant industry guidance or experience available. Using a converted tanker in a regular, more frequent loading and offloading cycle than was originally intended can introduce structural integrity issues to the process and marine piping systems as well. Infrastructure of varying age coupled with topside modules and piping systems designed according to fixed platform design code and experience also add to the integrity management challenges for such assets. When adopting risk-based integrity management on floating production storage and offloading (FPSO) process systems, these challenges can affect risk-based inspection methodology selection, the level to which it can be practicably applied, and failure mode determination. This paper describes Hess Corporation's (Hess) processes, practices, and risk application in the development of an integrity management system (IMS) for an aging FPSO topside located in West Africa.

This paper describes how one company developed and implemented a risk-based integrity management system and applied it to operated facilities within the Gulf of Mexico.The challenges of maintaining integrity of offshore assets change constantly throughout the life of a facility. The adoption of an Integrity Management System that integrates both risk-based and prescriptive practices can allow an operator to identify changing integrity threats and apply proactive mitigation strategies in good time. Successful use of an IMS can enhance safe operation and regulatory compliance while maintaining up time during declining production.The paper describes the challenges faced in applying these techniques within the Safety and Environmental Management System regulatory regime and Gulf of Mexico operating culture and reviews Lessons Learned in developing and implementing the Integrity Management SystemsThe paper describes how the IMS facilitated the assessment of platform condition and remaining life and how this in turn influenced the remediation requirements and subsequent maintenance and integrity activities required to facilitate life extension.