Standardized Freestanding Hybrid Riser Systems for Deepwater …€¦ · BP. 2010; Angola. 6,890;...

Standardized Freestanding Hybrid Riser Systems for Deepwater FPSOs

John Bob-ManuelSenior Engineer2H Offshore Engineering Ltd1st November 2011

Learn more at www.2hoffshore.com

Freestanding Hybrid Risers

2H overview

Why is there a need for them?

Configurations

Current examples

Alternatives


2H Overview

Riser and conductor systems specialists

Houston, Rio, London, Aberdeen, Kuala Lumpur, and Perth

170+ high quality engineers

Unique combination:Complex analysisEquipment detail design

Part of Acteon Group


18 specialist subsea Companies

£310m Turnover

51% owned byFirst Reserve Corporation

Linking Subsea Services

Acteon Group


Deepwater Riser Design Challenges

Long unsupported lengthsHigh pressuresDesign life of 20-30 yearsEnvironmental loading

CurrentWave

FPSOVessel motionsVessel offsetsPayload limitationsRiser-FPSO interfaces

High extreme stressesHigh fatigue damage rates

Vessel Offset

Wind

Current

Waves


Deep Water Riser Design Options: Flexible Risers

Compliant responseNot fatigue sensitiveInstallation friendlyLimitations

Water depthPressureDiameterTemperature

ExpensiveReliability? Free-Hanging Lazy Wave


Deep Water Riser Design Options: Steel Catenary Riser (SCR)

6-30” diameter1,000 – 10,000ft water(8,000ft installed)Sensitive to vessel and environment

Extreme loadsFatigue motionsVIV

Payload impact on host facilityComplex vessel interface

Flex jointStress joint

Heave optimised vessels (Spar, TLP)


Freestanding Hybrid Riser


Free Standing Riser Configuration


Single Line and Bundle FSHRs


Buoyancy Tank

Maintain riser verticalitySteel plate structureFlat or hemispherical endsPressure balanced designCompartmentalised

Design up to:40m tall6m diameter~700Te upthrust

Limited by:Fabrication siteHandling / Installation restrictions


Upper Assembly - Conventional

Tubular frame structure

Loading interface between:Top of riser pipeBuoyancy tankFlexible jumper

May require:Articulation connectionFlexible jumper pull-inIntervention entry point

Design up to:23m tall55Te


Upper Assembly - Alternatives


Lower Assembly

Tubular frame structure

Loading interface between:Bottom of riser pipeFoundationRigid base jumper

May require:Articulation connectionStress jointRiser base gas lift

Design up to:5m – 20m tall10 - 30Te


Rigid Base JumperSteel pipe / induction bends

Accommodate relative movement between riser and flowlinePipeline expansionRiser motions

Critical fatigue mechanismsRiser motions (drift / riser VIV)Jumper VIV Thermal cyclingSlugging


Rigid Base JumperSteel pipe / induction bends

Accommodate relative movement between riser and flowlinePipeline expansionRiser motions

Critical fatigue mechanismsRiser motions (drift / riser VIV)Jumper VIV Thermal cyclingSlugging


Freestanding Riser EvaluationAdvantages

Decoupled from vessel motionsNot sensitive to environmental loadingExcellent fatigue performanceLow vessel payloadPre-installableFlow assurance flexibility

Large insulation thicknessesPipe-in-PipeCRA lined pipe

Local content PilesBuoyancy Can

Opportunity for design standardisation

DisadvantagesLarge spatial requirementClearance issuesIncreased design complexityHigh CAPEX compared to SCRInstallation challenges

Large componentsOverall lift weight/height


Benefits of Standardising Freestanding Hybrid Risers

Differentiate on ability to install pipe efficiently, NOT ability to:

Develop riser conceptsConduct detail design of products/components

Allows Operator to drive technical solution

Risk & responsibility fairly distributed:Operator - Global system performanceContractors - Component design & installation

System engineered once

Increased market competition

Wider application of ‘available’ installation vessels


Freestanding Risers to Date

Type Field Status Owner/Field Operator

Yr. Installed Region

Water Depth Vessel

(ft) (m)

Green Canyon 29/Garden Banks 388

De-commissionedPlacid Oil Company/Ensearch

1988/1994 GoM 1,529/2,096 466/639 Semi-Sub

Girassol Operating Total Elf 2001 Angola 4,430 1,350 Spread Moored FPSO

Rosa Operating Total Elf 2007 Angola 4,430 1,350 Spread Moored FPSO

BP Greater Plutonio Operating BP 2007 Angola 4,300 1,311 Spread Moored FPSO

Kizomba A/B Operating Exxon 2003/2005 Angola 3,330 to 4,200

1,006 to 1,280

Spread Moored FPSO

*Block 31 NE Fabrication BP 2010 Angola 6,890 2,100 Turret Moored FPSO

Roncador P-52 Operating Petrobras 2007 Campos Basin 5,906 1,800

Semi-SubFPU

*Cascade/Chinook Detailed Design/Execute Petrobras 2011 GoM 8,531 2,600 Turret

Moored FPSO

*To be installed

Bun

dle

Sing

le L

ine


Kizomba A & B - Exxon

First field to use SLORKizomba A – 5 risers

1 x Water Injection 2 x Water Injection 2 x Gas Injection

Kizomba B - 5 risersCOR - riser base gas lift2 x Production PIP 1 x Test PIP2 x Water Injection

Kizomba Satellites – Two additional CORs (2011 installation)


Kizomba A


Girassol Riser Tower


BP Block 18 Riser Bundle


Other Developments

Petrobras Cascade & ChinookFirst FPSO in GoM2600m water depthDisconnectable turret required for hurricane event5 single line freestanding risers Freestanding Riser is ‘enabling technology’

BP Block 31 PSVMDeepest SLHRs in WoA2000m water depth9 SLHRsExternal bow mounted turreted FPSO


Alternatives/Developments

Freestanding RisersReduced cost - top assembly optimisationGrouped arrangement

SCRWeight optimisedLazy Wave – Shell BC10Buoyancy supported


BSR – Riser Supporting Buoy

Concept developed in the 90’s by DeepStar for 1000m.

Being evaluated by Petrobras for Guara and Iara


BSR is a hybrid concept that takes advantage of the best features of SCRs and flexibles.

SCRs: Less expensive thanflexibles. Suitable for use in ultra-deep waters with largediameter sizes.

Flexible jumpers have excellentfatigue behavior.

BSR – Riser Supporting Buoy


FPSO Interfaces

Key interfacesFlexible end terminations and bend restrictors

Key parameters affecting designTurret vs spread mooredPosition of riser hangoffSpace for riser end terminationsMaximum hang off weightVessel motionsHeading analysisMooring analysis

Interface mechanism with FPSO contractor needs establishing early on!


Thank you for your time.

Questions….

Further information:

2H Offshore Engineering Limitedwww.2hoffshore.com

+44 1483 774900


http://www.2hoffshore.com/

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Standardized Freestanding Hybrid Riser Systems for Deepwater …€¦ · BP. 2010; Angola. 6,890;...

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