hmpe lines in deepwater modu mooring offshore brazil · hmpe lines in deepwater modu mooring...
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HMPE lines in deepwater MODUmooring offshore BrazilFaster relocations, reliable performance and survival
Sérgio Leite – Lankhorst Ropes – PortugalJorn Boesten – DSM Dyneema – Netherlands
Tuesday, 4th October 2011OTC Brasil 2011 – Rio de Janeiro
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 2/(20)
Agenda
• Why
• Drivers adoption HMPE in temporary platformmooring
• Properties rope with HMPE
• Case – system performance and storm stiffness
• Case – creep
• Operational benefits and cost savings
• Conclusions
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 3/(20)
Why HMPE offshore Brazil
• Need to efficiently drillhundreds of wells
• Deeper water depths
• 2-300 kilometersoffshore, logisticalchallenges
• Rising costs ofdeepwater MODUmoorings
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 4/(20)
Why HMPEFaster mooring operational cost savings
Cost factor Potential savingsCost factor Potential savings
Anchor handlingvessels
Use smaller ones
Less trips to shore
Use less time (fasterinstallation)
Installation &decommissioningtime
Faster using HMPE versuspolyester
(up to 40% faster)
Rig down time Faster hookup(twice as fast)
Connecting hardware Smaller (or no) buoys
Watch circle Smaller
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 5/(20)
MODU rope with HMPEConstruction and material
Construction: Gama 98
• Core: 12 Braided sub-ropes(laid parallel) from SK78 byDSM Dyneema
• Jacket: Overbraidusually Polyester, can be othersynthetic material
• Filter:Between core and the jacketrestricts the ingress of particles
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 6/(20)
MODU rope with HMPEProperties (with PET jacket)
General CharacteristicsStrength wet/dry 100 %Specific gravity ~1.04 (buoyant)Elongation Very LowWater absorption NoneAbrasion Resistance ExcellentMelting Point 140 oC HMPE
260 oC PET
Chemical Resistance (Jacket)Acids GoodAlkalis ModerateOil/Gas Very Good
Ultra Violet Resistance Excellent
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 7/(20)
MODU rope with HMPELoad extension properties
• Extension at break of 2%
• Similar to steel wire rope
• 3-4 times less thanPolyester
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 8/(20)
HMPE – PET mooring evaluationDelmar study
• Comparative study investigating performance ofHMPE, PET and hybrid moorings
• API RP 95F 2006 metocean conditions
51372mSK78
6915mChain
Typical mooring line
(2286 m WD)
Rig wire 610m 1,2
PET 915m 4
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 9/(20)
MODU rope with HMPE3-4 times stiffer than Polyester
• 3-4 times stifferthan Polyester
• Up to 50%reduction onwatch circle
Typical EA Values (*MBL) for rope with PET or HMPE
Stiffness Mode Polyester EA SK78 EA
Drift 15 60
Storm 30 105
Intact System Performance Curves
7500' water depth
0%
1%
2%
3%
0 200 400
Horizontal Tension (kips)
MO
DU
Off
se
t(%
wa
ter
de
pth
)
Polyester
HMPE
Hybrid
Catenary
Steel Semi-Taut
-33%
-50%
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 10/(20)
Intact System Performance Curves
7500' water depth
0%
1%
2%
3%
0 200 400
Horizontal Tension (kips)
MO
DU
Off
se
t(%
wa
ter
de
pth
)
Polyester
HMPE
Hybrid
Catenary
Steel Semi-Taut
-33%
-50%
Intact system performance curves2268 m water depth
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 11/(20)
Case - storm stiffnessGOM - MODU mooring reliability - API 95F 2006
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 12/(20)
Case - storm stiffnessGOM - MODU mooring reliability - API 95F 2006
• An HMPE MODU mooring system can be engineered tohave similar performance and survivability as a PETsystem in deepwater applications– with the benefit of improved station keeping
– also under the updated (more severe / post Katrina) APIstorm conditions in the GOM
– Hybrid configuration allows the system designer the ability toengineer system stiffness to optimize FOS and station keeping
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 13/(20)
HMPE – Technical challenge: creepCreep case study
• All HMPE fibers will creep under permanent load
• SK78 (low creep grade) is the only HMPE fiberapproved by Bureau Veritas and ABS for MODUmoorings
1,2610mRig wire
51372mSK78
6915mChain
Typical mooring line
(2286 m WD)
Buoy - 3
PET 915m 4
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 14/(20)
HMPE – Technical challenge: creepCreep case study – less than 0,1% line elongation in one year
• All HMPE fibers will creep under permanent load
• SK78 (low creep grade) is the only HMPE fiberapproved by Bureau Veritas and ABS for MODUmoorings
Calculated creep (m)
(3812m line length)
1 year 1.4
5 years 5.5 – 9.8
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 15/(20)
HMPE MODU rope compared to PET3x lighter and transport volume reduced by 40%
• 630t MBL rope, 1200 m
• Reduction on the reeldimensions – from Ø 4.0 mflange (Polyester) down to Ø 3.0m flange (HMPE)
• Rope weight decreases from 19tto 7t
(m)
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 16/(20)
Why HMPEFaster mooring operational cost savings
Cost factor Potential savingsCost factor Potential savings
Anchor handlingvessels
Use smaller ones
Less trips to shore
Use less time (fasterinstallation)
Installation &decommissioningtime
Faster using HMPE versuspolyester
(up to 40% faster)
Rig down time Faster hookup(twice as fast)
Connecting hardware Smaller (or no) buoys
Watch circle Smaller
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 17/(20)
HMPE in temporary platform mooringDrivers for adoption of HMPE versus PET
Value
• Reduced operational costs when relocating drilling rigs
• Improved station keeping Enabling for moorings in water >2500meter deep
• Special grade developed for optimum performance in MODUmooring: Dyneema® SK78
Reliability
• Approved by Bureau Veritas and ABS for MODU moorings
• Use of rope with Dyneema® accepted by major operators such asShell and Petrobras
• Mooring analysis shows sometimes a polyester insert is needed forreduction of peak (storm) loads
ABS ApprovedABS ApprovedABS ApprovedABS Approved
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 18/(20)
Operational savings versus polyesterSystem cost evaluations
Higher Capex cost of a MODU mooring system withHMPE is offset by Opex savings with every rigrelocation
0
20
40
60
80
0 5 10
Relocations
Ca
pe
x+
Op
ex
co
sts
(M$
)
Dyneema®
PET
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 19/(20)
Conclusions
• Lankhorst ropes and DSM Dyneema have over 10 yearsexperience in supplying synthetics to offshore industry
• Gama 98® rope with SK78 from DSM Dyneema is aproven mooring line for deepwater moorings,accepted by major operators such as Petrobras
• Hybrid HMPE-PET mooring line design allows mooringengineer to optimize between station keeping andstorm survivability
• Higher initial CAPEX will be offset by OPEX savingsthrough ie faster installation and hook up
OTC 22486 · HMPE mooring lines · S Leite, J Boesten · 20/(20)
Sérgio Leite – Lankhorst Ropes/Offshore Division – [email protected]
Jorn Boesten – DSM Dyneema – [email protected]
Obrigado – Thank you