MCE Deepwater Development 2016
Time-domain Nonlinear Coupled
Analyses Covering Typical Mooring and
Riser Configurations for FPSOs
Author: Fan Joe Zhang
Presenter: Styrk Finne
DNV GL - Software
PAU, FRANCE 5-7 APRIL 2016
MCE Deepwater Development 2016
Contents
Typical analysis for the design of FPSO mooring, riser and offloading
system
FPSO mooring alternatives
Spread mooring (MPM)
Turret mooring (SPM)
Oil offloading Options
Tandem offloading
Side-by-side offloading
Catenary Anchor Leg Mooring (CALM) terminal
Examples
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Analysis for the design of FPSO mooring, riser and offloading system
Mooring alternatives Offloading
Spread mooring (MPM) Single Point mooring (SPM) Tandem CALM buoy
Mooring and riser Riser alternatives Side-by-side CALM buoy with shuttle tanker
SCR SCR CALM buoy with FTB and shuttle
Bending stiffener and jumper TLR tanker
FPSO coupled with TLP SHLR
Accidental analysis
Detachable turret
SPM with DP
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Typical workflow
FEM models
Modelling (GeniE) Time domain coupled analysis (DeepC and Sima)
Hydrodynamic coeff.
Added Mass and Damping
Hydrodynamics (HydroD)
1st and 2nd wave forces
Wave drift damping
Etc. 5
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Mooring Types
Spread Mooring Turret Mooring
Dalia
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Offloading alternatives
Tandem Side-by-side
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Mooring system
Water depth 1,400 m
14 mooring lines
Non-collinear environment
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Spread mooring with risers and umbilicals
14 mooring lines, 8 production risers, 4 gas injection riser,
4 water injection risers, 4 umbilicals
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Results and post-processing
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Results and animation
Node Displacement Effective Tension
Bending My Shear Sz
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With TLP
2 floaters
TLP and FPSO
Positioning system
14 mooring lines
12 tendons
Risers and umbilicals
8 production risers for FPSO
11 TTR for TLP
4 gas injection riser and 4 water injection risers
4 umbilicals for FPSO
5 connecting umibilicals
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Results
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Turret mooring and riser analysis
Mooring analysis
Riser configurations[4]
Steel Lazy Wave Riser (SLWR)
Tension Leg Riser (TLR)
Single Line Hybrid Riser (SLHR)
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MCE Deepwater Development 2016
SLWR
Compliant riser system
An alternative to SCR
Lower stress and fatigue damage near the touch
down point (TDP)
Maximum vertical motion at the riser hang off point is
high in 100-year hurricane
Optimized by
Examining riser performance in extreme sea states
Minimizing mount of buoyancy
Parameters of interests
Max and min effective tensions
Max Von Mises stresses
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MCE Deepwater Development 2016
Results
Preferable to [4]
Place the wave as close as possible to the seabed
Have enough buoyancy to maintain the wave shape up to
the extreme far position
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Tension Leg Riser (TLR) [5]
In the case study, 6 SCR was used, departing on each
side of the buoy.
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Decoupling motions of FPSO
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Single Line Hybrid Riser (SLHR) [5]
A hybrid decoupled riser system
Decoupled from motions of FPSO
SLHR composed of
Vertical rigid pipe
Stress joint and suction pile
Gooseneck connecting riser and flexible jumpers
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Modelling
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Brief comparison
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Breaking line transient analysis
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Comparison Intact and damaged, motions
10% water depth: 137.4m (100m) 14% water depth: 191.8m (145m)
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MCE Deepwater Development 2016
SPM FPSO with rotatable turret model
Turret
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Detachable turret (e.g. MUNIN FPSO)
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Turret motions
-97 m
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Side-by-side offloading with SPM FPSO
Multi-body coupling
Hydrodynamic coupling
Fenders
Connecting lines
Etc.
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Hydrodynamic coupling calculation in Wadam
11 12
21 22
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CALM buoy
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More complex setting
3 bodies
20 slender structures
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Decoupled motion of SPM and FTB
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Dynamic loading on the flowlines reduced
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Summary
Sesam from DNV GL covers comprehensive analysis of FPSO mooring
and offloading alternatives including
Spread mooring and turret mooring
Turret mooring with thrusters
SCR, FTB, Hybrid, etc.
Global and local analysis easily simulated
Bellmouth and jumper analysis
Local turret analysis
Mooring (riser) disengaged transient analysis provides more
confidence
Detachable turret analysis
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References
1. L.T. England, A.S. Duggal, L.A. Queen, (2001) A Comparison Between Turret and Spread Moored
F(P)Sos for Deepwater Field Developments, Deep Offshore Technology 2001.
2. O. Ihonde, J. Mattinson, L.T. England, (2002) FPSO mooring & offloading system alternatives for
deepwater West Africa, 6th Annual Offshore West Africa Conference.
3. A.S. Duggal, C.O. Etheridge, J. Mattinson, (2001) A New Deepwater Tanker Loading System for
West Africa, Offshore West Africa 2001.
4. C.A. Zimmermann, D. Petruska, A.S. Duggal, (2002) Effective Riser Solutions for a Deepwater
FPSO, OMAE 2002.
5. C.A. Zimmermann, C.L. Garnero, R.C. Mark (2001) Tension Leg Riser System An Effective
solution for Deepwater Risers, OMAE 2001.
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