Turret-Moored FPSOs are more and more used for deepwater developments worldwide, with consideration of disconnectable turrets for harsh environment applications. This trend makes the interactions between FPSO and riser system, and the optimized selection of the riser system, of greater importance.
The paper provides a review of the various riser systems that can be considered for turret-moored FPSOs: proven systems, both coupled (flexibles and rigid risers) and uncoupled systems (hybrid single and multiple riser systems), and new riser concepts. These systems are described in terms of design and functionalities; fabrication and installation methods are presented.
Pros and Cons for these riser systems are discussed, with consideration of the particular challenges brought by turret-moored FPSOs (e.g. large floater motions, riser hang-off geometry constraints at turret, hang-off loads, riser interferences, riser pre-installation, turret disconnection constraints). Elements for selection of the most appropriate riser system are proposed, considering a range of project specificities.