Mooring failures have been a recurring issue in the offshore industry, and failures continue to occur across the offshore Floating Production System (FPS) fleet. Many of these recurring failures appear to be from similar degradation mechanisms as past events. To better understand these trends and learn from these events, DeepStar® Project 20401 - Database of Mooring Integrity Issues and Lessons Learned was initiated.
The project primarily consisted of the collection and assessment of mooring integrity data on failures, pre-emptive replacements and repairs observed on FPS permanent mooring systems. Additionally, chain corrosion/wear data was collected and summarized as part of the project. When available the data was collected from published sources. However, most of the integrity data came from the eight operator and mooring consultancies companies participating in the project.
This paper describes the project data collection, the deliverables and key observations from the mooring integrity database developed as part of the project. The observations presented within the paper provide unique insight into predominate degradation mechanisms, observed consequences and estimated failure rates of mooring lines.