There has been a growing number of projects in the offshore industry that use disconnectable buoy systems. The advantage of such a system is that in case a large hurricane or typhoon is moving towards the FPSO it can be disconnected from its risers and mooring quickly to avoid any damage to the facility. In this disconnection phase the turret buoy is detached from the vessel and drops to a safe depth of 100-200m below the surface. The FPSO is then moved to a safe area until the storm has passed by. Afterwards the buoy can be picked up again and reconnected to the FPSO in a short period of time.
It is challenging to predict the buoy behavior during disconnection and reconnection without performing extensive model tests at multiple scales. The present JIP proposal focuses on the hydrodynamic design aspects of the buoy in disconnection and reconnection phase and aims to deliver a methodology to predict the behaviour in the design phase of the project.
Last JIP Meeting held March 2014 in Monaco which presented updates on the Computational Fluid Dynamics model from full scale measurements. Ways forward include a sensitivity study for the presence of moonpool, pitch roll oscillations close to the FPSO, and horizontal offset of the FPSO in the analysis. To achieve these new model tests are being conducted and will be analyzed to update the prediction models.