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The Low Motion FPSO
(LM-FPSO)
The SCR and TTR Friendly Floater in Harsh
Environment
Alaa Mansour, Ph.D Marine Engineering Manager
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 2
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 3
Field Development Challenges
Lack of Infrastructures/Remoteness
Requirement for DVA to wells
Water depth
Persistent swells
Harsh environment
Large number/diameter risers
Inherently high dynamic floater
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
5 15 25 35
Hea
ve (
m/m
)
Period (s)
0 22.545 67.590 112.5135 157.5180
0
0.5
1
1.5
2
2.5
5 15 25 35
Ro
ll (d
eg/m
)
Period (s)
0 22.5
45 67.5
90 112.5
135 157.5
180
Slide 4
Riser feasibility
FPSO or FPU+FSO/FPSO
TTR feasibility or Separate DTU
FPSO Heave FPSO
Roll
Field Development Challenges
Question?….
Can we develop FPSO that offers:
High oil storage capacity and deck payloads
Superior motion response - TTR/SCR/mooring friendly
No turret or swivel
Large number/ large diameter risers
Fast deployment & decommissioning
Quayside integration
Simple and efficient hull form
Maintain simple topside layout
Commercially attractive (CAPEX & OPEX)
Low risk and minimum or no schedule impact
Slide 5
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 6
The LM-FPSO Design
Slide 7
Conventional hull construction
Conventional Topside
Conventional Mooring System
Short Tendon Pipe No couplings
Solid Ballast tank (SBT)
Tendon Bottom receptacle
Tendon Top Connector
SCRs / Umbilicals
The LM-FPSO Constructability
► Simple hull form
► Stiffened plate structure
► Simple fabrication
► SBT fabricated independently
► Solid ballast is added in SBT
► Hull modules are integrated above SBT
► Topside integrated
► Mooring chains are used to connect SBT to hull
► Dry dock is flooded
Slide 8
The LM-FPSO Install-ability
Slide 9
Wet-tow
The LM-FPSO Install-ability
Slide 10
Positioning and Ballasting
The LM-FPSO Install-ability
Slide 11
Tendon Installation
The LM-FPSO Performance
Slide 12
The mass of the SBT:
Maintains positive tendon tension in all design conditions
Ensures full coupling in heave, roll and pitch
Ensures full coupling in the slow motion surge/sway & yaw
Provides high stability (high GM) – less compartments
SBT mass and added mass
Long heave, roll and pitch natural periods
Significantly low heave roll/pitch motions
The relative motion in surge, sway and yaw
Limited to first order
Much less than TLP hull-to-foundation relative motions
► Very long Heave Natural period
► Significantly reduced heave response in WF
► Very long Roll Natural period
► Significantly reduced Roll response in WF & LF
Slide 13
Typical Heave Response Typical Roll Response
The LM-FPSO Performance
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
6000 6050 6100 6150 6200 6250 6300 6350 6400 6450 6500
RY
[deg
]
Time [s]
DM-FPSO Hull vs. SBT, Pitch Motion
FPSO RY SBT RY
The LM-FPSO Performance
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
6000 6050 6100 6150 6200 6250 6300 6350 6400 6450 6500
Z [m
]
Time [s]
DM-FPSO Hull vs. SBT, Heave Motion
FPSO Z w/o Mean
SBT Z w/o MeanTypical Heave
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
6000 6050 6100 6150 6200 6250 6300 6350 6400 6450 6500
RX
[d
eg]
Time [s]
DM-FPSO Hull vs. SBT, Roll Motion
FPSO RX SBT RXTypical Roll
Typical Pitch • Full coupling in heave, roll and pitch modes
• Very low heave roll/pitch motions, less than a third that of Spar, almost TLP like
Slide 14
0
5
10
15
20
25
30
35
6000 6200 6400 6600 6800 7000 7200 7400
X [
m]
Time [s]
DM-FPSO Hull vs. SBT, Surge Motion
FPSO X SBT X
0
5
10
15
20
25
30
35
6000 6200 6400 6600 6800 7000 7200 7400
Y [m
]
Time [s]
DM-FPSO Hull vs. SBT, Sway Motion
FPSO Y SBT Y
The LM-FPSO Performance
Slide 15
Typical Surge Typical Sway
-1.00
-0.80
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
6000 6050 6100 6150 6200 6250 6300 6350 6400 6450 6500
RZ
[deg
]
Time [s]
DM-FPSO Hull vs. SBT, Yaw Motion
FPSO RZ SBT RZ
Typical Yaw
• Full coupling in Surge, Sway and
yaw modes • Relative motion is quite small
0
5000
10000
15000
20000
25000
30000
200 2200 4200 6200 8200 10200
Bo
tto
m T
ensi
on
[kN
]
Time [s]
Critical Tendon Bottom Tension
Critical Tendon Bottom Tension
The LM-FPSO Performance
Slide 16
• Tendon tension is positive even in survival conditions
• LM-FPSO to SBT Relative motion is less than that of TLP-to-Foundation.
Tendon Tension
TLP vs LM-FPSO Dry Tree & Harsh Environment
1000 yr condition
The LM-FPSO Performance
Slide 17
VIM Response
Current speed = 1.1 m/sec Vr = 3.7 A/D = 0.07
The LM-FPSO Performance
Slide 18
SBT Structural Analysis
The LM-FPSO Performance
Slide 19
SBT Structural Analysis
The LM-FPSO Economics
Compared to the corresponding conventional FPSO:
Slide 20
Dry Tree – Harsh Environment
Wet-Tree Persistent Swell
Hull Steel 10-15% Increase -
SBT Steel (% of hull steel) 14% 5%
Solid Ballast (% of Displacement) 25% 15%
Tendon system TIC/tendon $4.1MM $4.1MM
Offloading Buoy cost $100MM Increase
Mooring system $15MM Increase $25MM Reduction
SLWR to SCR (per riser) $15MM Reduction $15MM Reduction
Turret $250MM Reduction -
Eliminate DTU (CAPEX) - Each $500MM Reduction -
Topside cost $50MM Reduction -
OPEX $100MM Reduction? -
Decommissioning $100MM Reduction -
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 21
Dry Tree LM-FPSO in South China Sea
Water depth = 500 m
Topside payload = 25,000 MT
1.0 MMBBL Storage
15 TTRs
1 Multiphase production SCR
Environment: .
Slide 22
1,000 Yr 100 yr
Hs (m) 15.8 13.5
Tp (sec) 16.5 15.2
Ws (m/s) 51.6 49.8
Cs @ surface (m/sec) 3.9 2.4
Dry Tree LM-FPSO in South China Sea
Slide 23
L x w x H (m) 105.0 x 105.0 x 51.5
Corner radius (m) 10.5
Draft / Freeboard (m) 33.5 x 22.0
Center Well (L x W) (m) 60.7 x 60.7
Hull Lightship Wt (Mt) 44,330
Displacement (Mt) 227,768
L x W x H (m) 142.5 x 105.0 x 3.7
Center Opening L x W (m) 24.4 x 14.6
SBT steel Weight (Mt) 6,076
Solid ballast weight (Mt) 49,556
Mooring (-) 16 Chain-PE-Chain
Platform Chain Dia x L (mm x m) 162 mm R4S x 100 m
Polyester Dia x L (mm x m) 305 mm x 750 m
Platform Chain Dia x L (mm x m) 162 mm R4S x 150 m
Tendons (-) 16 @ 44"OD x 1.7"
Length (m) 88.0
Wt weight (Mt) 12.0
Heave Np (sec) 25.0
Roll/Pitch Np (sec) 46.0
GM (m) 31.9
Integrated Platform Lightship weight (Mt) 71,134
Hull+SBT Draft (inc. SB) (m) 12.3
Solid ballast is added in dry dock (-) YES
Lightship Draft (no solid ballast) (m) 4.9
The Hull
The SBT
The Mooring System
System Natural periods
Pre-service Key Figures
Dry Tree LM-FPSO in South China Sea
Slide 24
Heave RAO Roll Response
Dry Tree LM-FPSO in South China Sea
Slide 25
Variable Unit 1,000-yr 100-yr
Max offset % 11.7% 8.7%
Max SCR Porch Velocity (m/s) 1.7 0.9
Max heave (SA) (m) 4.0 3.1
Max combined Roll/pitch (SA) (deg) 3.9 3.4
Max Yaw (deg) 1.8 1.8
Max Hull-SBT rel. horizontal motion (m) 18.8 13.5
Minimum tendon tension (Mt) -170 599
Max Tendon Tension (Mt) 6,411 5,178
TTR dynamic Stroke (m) 7.2 4.6
Max Keel Joint Reaction (Mt) 108 59
Max Von Mises Stresses (MPa) 551 358
Dry Tree LM-FPSO in South China Sea
Slide 26
The System Performance
1,000-yr Critical Event 100-yr Critical Event
LM-FPSO + ONE TLP Cost Delta
Fabrication cost delta (Hull + SBT) $50MM
Transportation & Installation $10MM
Solid Ballast TIC (at quayside) $5MM
Mooring system delta $15MM
Tendon cost including Installation (TIC) $65MM
Offloading buoy TIC $100MM
Additional Tensioner costs $24MM
Eliminate one TLP (Hull& Mooring T&I) -$500MM
Topside saving -$50MM
No turret -$250MM
No FTL from One TLPs -$30MM
Decommissioning saving of 1 TLPs -$100MM
OPEX delta -$100MM??
Total Delta -$761 MM
Dry Tree LM-FPSO in South China Sea
Compared to a Turret-Moored FPSO + TLP in SCS
Slide 27
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 28
The Semisubmersible Version - TLS
Similar technology is applicable to conventional semisubmersibles designs to significantly improve their motions – Tension Leg Semisubmersible (TLS)
Slide 29
The TLS Semi – In-place
Tendon Porch
Tendon bottom receptacle
The Semisubmersible Version - TLS
Slide 30
The TLS Semi – Pre-service
The Semisubmersible Version - TLS
Slide 31
0.0
1.0
2.0
3.0
4.0
0 5 10 15 20 25 30 35 40 45
Period (sec)
Heave R
AO
(ft
/ft)
0
500
1000
1500
2000
Wave E
nerg
y S
pectr
um
(ft
^2-s
ec/r
ad
)FHS SemiConventional
SemiSpar
Wave
Energy
H1000
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 32
The Business Case
FPSO market share is greater than the combined FPU market
Potentially replace the common development scheme in west Africa (TLP+FPSO) … big market share (Example Maersek Chissonga, Hess Ghana)
Attractive solution for Liuhua development in SCS
Attractive solution for Talisman development in Vietnam
No feasible riser solution on FPSO for ultra-deepwater (Example Petrobras Pre-salt)
Industry is developing FPSO with SCRs for the GoM
Enable dry tree Semi with potential application (Mad Dog 2, Shenandoah, ..etc)
Improved semisubmersible response in wet tree application (CVX Jansz Io, Equus,…etc)
Slide 33
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 34
Scope and Required Funding
Develop a basis of design
Develop a LM-FPSO design that meets the BOD.
Perform compartmentations and stability analysis
Perform hydrodynamic and mooring analysis
Perform TTR analysis
Prepare model test specs (wind tunnel test, wave basin test, and towing tank test)
Perform Tendon top and bottom connector fatigue (ongoing)
Perform structural analysis (ongoing)
Perform model tests
Perform model test calibration
Verify the design based on model test to ensure it still meets the BOD
3D rendering
Presentation and marketing material
Slide 35
Scope and Required Funding
RDC contribution of $178K (55%) with WP/INTECSEA covering:
* $55,000 USD in cash
* $55,000 USD in-kind
Potentially RDC can contribute $200K (62%) with WP/INTECSEA covering the $121,810 (38%):
* $33,000 USD in cash
* $55,000 USD in-kind
Slide 36
Outlines
Field Development Challenges
The Low Motion FPSO (LM-FPSO)
• The Design
• The Constructability
• The Install-ability
• The Performance
• The Economics
Case Study: Dry Tree LM-FPSO in South China Sea
The Semisubmersible Version - TLS
The Business Case
Scope and Required Funding
Concluding Remarks
Slide 37
Concluding Remarks
The LM-FPSO is an enabling solution for TTR and SCR on FPSOs in harsh environment
It avoids the need for a separate DTUs. Compared to FPSO+TLP a $760 MM saving is estimated
The LM-FPSO offers
• High oil storage capacity and deck payloads
• Superior motion response - TTR/SCR/mooring friendly
• No turret or swivel
• Large number/ large diameter SCRs
• Fast deployment & decommissioning
• Quayside integration
• Simple and efficient hull form
Slide 38
Concluding Remarks
The LM-FPSO offers (cont.)
• Maintain simple topside layout
• Low risk and minimum or no schedule Impact
• Flexible ballast compensation capacity
The LM-FPSO & TLP when project ready will be a game changer to the industry
Required funding is about $55K USD in Cash and $55K USD in-kind contribution based on funding of $178K USD from RDC
Slide 39
INTECSEA Floating Systems
Alaa M. Mansour, Ph.D.
Marine Engineering Manager
575 North Dairy Ashford Rd.
Houston, TX77079
USA
1 281-206-8455 (O)
alaa.mansour@intecsea.com
Contact Information
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