FPSO riser and mooring arrangement

 

 

Attached FPSO vessels

 

Two options exist for FPSO stationkeeping - the great majority of existing FPSO’s employ a fixed mooring system using anchors and anchor lines; a few rely on dynamically positioned systems that employ a series of thrusters and positioning technology (satellite, GPS, etc.). The fixed mooring system can be further described as permanent or disconnectable.

 

Most FPSO’s deployed to date (and planned) are permanently moored, that is, they are designed to remain at the location throughout all anticipated environmental (weather) situations; there are few that have been designed to be disconnected under severe weather circumstances such as typhoons and hurricanes, or threat of icebergs.

 

When FPSO works, it needs to be attached to the turret with two types-internal or external. Both types allow the vessel rotates around the turret. It is means that the FPSO can turn to a certain angle to the storm and the waves when the storm comes, which can effectively reduce the motion of the vessel. The turret is also the interim station of the pipe and the vessel. So it does make sense for the vessel to be attached to the turret.

 

Nowadays, the force and relative motion between the turret and the vessel is one of the most discussed topics in the FPSO field.