2. Learning Outcomes
1. Explain the key considerations in the FPSO layout and
design
2. Explain the features of an internal and external turret for
a FPSO
3. Explain the considerations for deciding whether to use
internal turret or external turret for a FPSO
4. Explain how the internal turret may be placed along the
length of a FPSO
3. 1. Explain the key considerations in the
FPSO layout and design
5. FPSO Layout and GA
Key Issues
Deadweight
Cargo (storage) capacity
Equipment (payload) capacity
Hull structure - Global and local strength
Main vessel layout - Deck space - Location of accommodation (NB)
Location of turret % LBP
Need to be considered
Hull form, fineness and sea-keeping considerations (NB)
Bow shape, free board (forecastle & ship side) (NB)
Green water protection
NB = Issues where scope
for choice exists with new-
builds
8. FPSO Layout - Hull systems and utilities
Layout of major features (NB)
Accommodation and Turret
Main marine systems & utilities
• Cargo & ballast & Pump room
• Main Power, emergency power,
• Fire pumps.
• Heating, Ventilation and Air-Con (HVAC)
• Inert Gas (IG)
Other spaces and services required for auxiliary equipment and shared systems
Vessel upper deck piping arrangements (pipe rack integration)
Integration of hull marine and topsides systems
Power/fuel
Control and safety systems
Emergency power
NB = Issues where scope
for choice exists with new-
builds
9. Interface with Topsides equipment and systems
There are a number of key issues that need to be considered by the hull design process
Structural integration of topsides support stools & module support structure into hull structure layout
Hydrostatics considerations of required maximum topsides weight and Centres of Gravity
Layout and space considerations in the area of the vessel upper deck
Systems integration of hull and topsides systems
10. Examples of Layout Considerations
1. Vessel Motions
Minimise the effects of vessel motions
– The process equipment located as close to midship
2. Helicopter Operations
– Accommodation block with the helicopter platform must be located clear of
hazardous zones
– Ideally upwind of the flare stack
3. Metering arrangements
– Export (esp. North Sea) is always likely to be by tandem moored tanker and so
the offloading facilities as well as the metering arrangements will be at the
stern if the turret is near the bow.
12. 2. Explain the features of an internal and
external turret for a FPSO
13. Turret Technology
Turret and swivel systems (allow n x 360 degrees rotation) has been the key technology for
the deployment of FPSOs in all met-ocean environments
Turret allows vessel to weathervane – that is, to take up a position that aligns her heading
towards the dominant forces of wave, wind and current.
Weathervaning has the effect of minimising environmental loads on the station keeping
system, and minimises the most sensitive vessel motions – generally for a mono-hull – roll.
This has the effect of minimising disturbance to process equipment and personnel and
maximising the facility uptime.
14. Different Turret Types
Internal turrets
External turrets (forward of bow - normally)
Permanent or disconnectable
Yoke moored
15. Internal Turret
• An internal turret is convenient when a large number of
risers are to be installed, and therefore a large turret and
swivel assembly are required.
• An internal position also reduces the risk of slamming due to
the reduction of the effect of pitch.
• Internal turrets can be used in deep waters and the most
severe environments
– up to 18 m significant wave height
23. External Turret
• An external turret eliminates the CALM buoy and allows the
turntable and swivels to be directly attached to the vessel
bow or stern.
• Suitable for deep waters and large wave heights
– 12 m significant wave heights
• Can be used up to the point where the combined heave and
pitch motions may cause slamming on the bottom of the
turret (depending on vessel size and length, up to
approximately wave height).
25. External turrets - Baobab Ivoirien FPSO,
Baobab Oilfield (Ivory Coast)
Images courtesy of Modec/Sofec
970 m water depth
8-leg polyester
mooring
357,000 dwt tanker
conversion
2.0 million bbls storage
26. External turrets- FPSO Fluminense Brazil
Images courtesy of Modec/Sofec
800 m water depth
357,000 dwt tanker conversion
1.2 million bbls storage
27. External turrets - Cuulong MV9 FPSO,
Su Tu Den Field (Vietnam)
Images courtesy of Modec/Sofec
28. Turntable- Typical Lay-out
Includes for example:
Subsea Control Skids
Pipe headers
Control valves
Pig receivers
Pig launchers
Installation Winch
Images courtesy of Bluewater
29. Yoke Mooring
CNOOC Bohai Bay QHD32-6 FPSO (China)
Kome Kribi FSO
w/ Tower Yoke Mooring System
Images courtesy of Modec/Sofec
66 ft water depth
New-build vessel
1.0 million bbls storage
30. Disconnectable systems
SBM’s External and Internal solutions
External or Riser Turret Mooring Internal turret with disconnectable buoy
Images courtesy of SBM
31. The Riser Turret Mooring (RTM)
Cossack Pioneer
Location NW Shelf
Australia
Vessel size: 152,000 Dwt
Topsides
115,000 bopd
Images courtesy of SBM
35. Swivel systems
Swivel systems allow the transfer of:
Production fluids from the subsea equipment to the vessel
Export fluids from the vessel to the sub-sea infrastructure
Well/subsea management/control fluids e.g. methanol
Electrical signals for control and monitoring
Electrical power for driving subsea/down-hole equipment
Swivel systems allow n x 360 degrees rotation
Swivel manufacturers are pushing back the boundaries of pressure and temperature to:
~400+ bar
~120 ⁰C
42. What is going on inside a swivel?
Images courtesy of Bluewater
43. What is going on inside a swivel?
Images courtesy of Framo
44. 45
What is going on inside a swivel?
Stator Rotor
Roller Bearing
(3-race)
Wiper Seal
Dust/Grease Seal
Outer Seal
Backup
Sliding
Bearings
Stator Rotor
Roller Bearing
(3-race)
Wiper Seal
Dust/Grease Seal
Outer Seal
Backup
Sliding
Bearings
Images courtesy of Bluewater
45. 3. Explain the considerations for deciding
whether to use internal turret or external
turret for a FPSO
46. Internal Turret
• An internal turret is convenient when a
large number of risers are to be installed,
and therefore a large turret and swivel
assembly are required.
• Internal turrets can be used in deep
waters and the most severe environments
– up to 18 m significant wave height
• An internal position also reduces the risk
of slamming due to the reduction of the
effect of pitch.
External Turret
• An external turret eliminates the CALM
buoy and allows the turntable and
swivels to be directly attached to the
vessel bow or stern.
• Suitable for deep waters and large
wave heights
– 12 m significant wave heights
• Can be used up to the point where the
combined heave and pitch motions may
cause slamming on the bottom of the
turret (depending on vessel size and
length, up to approximately wave
height).
47. 4. Explain how the internal turret may be
placed along the length of a FPSO
48. 4. Explain how the internal turret may be placed
along the length of a FPSO
Pg 5-10:
• if the vessel is passive i.e. no Dynamic-Position (DP) thrusters or has
a minimum thruster capacity, the internal turret is positioned within
the first 25% of the vessel length from the bow in severe
environments
• if the vessel is active i.e. sufficient Dynamic-Position (DP) thruster
capacity, the internal turret is positioned just forward of midships
49. Key Questions
1. Explain the key considerations in the FPSO layout and design
2. Explain the features of an internal and external turret for a FPSO
3. Explain the considerations for deciding whether to use internal turret or
external turret for a FPSO
4. Explain how the internal turret may be placed along the length of a FPSO