High Pressure - High Temperature (HPHT) design is a significant new challenge facing the subsea sector, particularly in the Gulf of Mexico. For fatigue-sensitive applications, the current regulations in the Gulf of Mexico will require operators to compare the actual load cycles experienced by the HPHT component to the load cycles used in the design verification analyses. Should the analyses show that the HPHT equipment is experiencing loading combinations that are greater than those anticipated in the original design, a new service life (loads, time in service, and cycles) based on the actual loads and cycles needs to be developed.
The condition assessment in other industries is mainly inspection-based, while inspection of subsea equipment at fatigue-sensitive locations during operation may not be practical. Thus, load monitoring and condition assessment of subsea facilities is a major challenge that the subsea industry is facing.
Several assessment methods were evaluated as part of this study, including use of available monitoring technologies in combination with analytical methods. The key findings are summarized to help establish the proper Load Monitoring Program (LMP) for HPHT subsea applications.