Integrity assessment of the mooring lines and risers of floating production systems based on numerical models generated by retroanalysis of measured data: PART I – Retroanalysis procedure

In the offshore oil production industry, information regarding the actual configuration of the mooring lines and risers of floating production systems (FPS) is periodically collected from field observations and surveys using remotely operated vehicles (ROVs). Taking advantage of such information, this work presents a retroanalysis procedure that updates and calibrates numerical models to represent the updated as-laid configuration of the FPS. This procedure has been implemented in association with the in-house, non-commercial SITUA-Prosim software that employs uncoupled, fully coupled and hybrid analysis formulations. The steps of the procedure are automated within the software. The application of the procedure is illustrated in a case study considering a typical FPS representative of actual offshore scenarios. This retroanalysis procedure may be seen as the first stage for the development of a digital twin for FPS, and for the establishment of an integrity assessment methodology using the updated as-laid models. The integrity of the system can be continuously reassessed by performing a series of analyses to check whether the appropriate design criteria of mooring lines and risers are still being met.