All-flexible and hybrid solutions for Ultra Deep Water Simplified - - PowerPoint PPT Presentation

All-flexible and hybrid solutions for Ultra Deep Water

Simplified presentation

SUT

July 2006 Jean-Paul Ferraz

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Contents

Flexible pipe capabilities Hybrid Catenary Riser (HCR) Free Standing Hybrid Riser (FSHR)

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Flexible pipe capabilities

Objective

Define maximum water depth vs pipe internal diameter

Assumptions

Bottom risers and flowlines Rough bore pipes Sweet & sour services Design pressure (differential) / temperature : 3000 psi / 90°C Radii ≥ 2 x pipe natural radius (flowlines) 1.25 DAF during installation (flowlines) Limited Deep Blue VLS tension capacity Current manufacturing limits (weight, diameters, bending stiffness, etc.)

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Flexible pipe capabilities

Driving design issues

Collapse Lateral buckling Reverse end-cap effect (high strength tapes) Installation top tension for flowlines & utilization factor x damaging pull

Maximum water depth as a function of pipe internal diameter curves were removed

from this simplified presentation.

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UDW flexible pipes qualification, DIP tests

Pipe follower Test sample Dead weight First mark (reference point for the TDP for the dry annulus test condition).

1800 m

depth Seabed

TDP at the second mark (flooded annulus condition) Vessel offset: 40 m

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UDW flexible pipes qualification, DIP tests

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UDW flexible pipes qualification, DIP tests

18 different structures tested offshore Brazil 13 campaigns of the Sunrise 2000 laying vessel ~100 m long samples tested in dry and flooded annulus conditions WD from 1080 m to 2100 m ID from 4” to 11” 9” pipe qualified for 2100 m water depth

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Contents

Flexible pipe capabilities Hybrid Catenary Riser (HCR)

• Free Standing Hybrid Riser (FSHR)

Free Standing Hybrid Riser (FSHR)

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Hybrid Catenary Riser (HCR), an observation

Simple free hanging configuration: very localized high curvature variations Riser Top TDP

0,00 0,05 0,10 0,15 0,20 0,25

Riser Top Riser Base Touch Down Point

Curvature Position along riser

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Hybrid Catenary Riser (HCR), features

Riser concept (Technip’s patent) for

Ultra Deep Water applications Flexible jumper at top side Rigid pipe as intermediate section Flexible pipe at TDP

General technical benefits:

Flexible pipe allows a much smaller bending radius at the TDP Much steeper configurations Reduced top and bottom tensions Avoid use of flex or stress joints

SCR HCR

Flexible Rigid Flexible

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Hybrid Catenary Riser (HCR), advantages

Global configuration similar to that of Flexible Riser

Small hang-off angle Small bending radius at the TDP Same behaviour as common flexible free hanging configuration

Horizontal vessel motions induce little dynamic loads Vertical vessel motions induce most of dynamic response

Transferred to the bottom section of the riser If motions are important a small buoyant wave shape can be included

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Hybrid Catenary Riser (HCR), advantages

Flexible-rigid connections outside high curvature zones Flexible pipe bending deformations locally absorbed

Flexible pipe curvature variations at connections much smaller than at TDP No large moments induced in the rigid pipe

Simple connection design

Standard flanges Small bending stiffeners (more for handling than for dynamic behaviour) at intermediate connections No special design required for rigid pipe

All configuration (flexible + rigid) can be installed with Deep Blue vessel

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Hybrid Catenary Riser (HCR), driving parameters

Decoupled and optimized designs

Top riser flexible jumper: design driven by fatigue however with reduced tensions Intermediate rigid section: reduced stress due to curvature variation absorbed by flexible pipe Bottom flexible section: design typically driven by collapse and compressive loads

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HCR vs SCR vs flexible risers study case

Water Depth 2750 m; offshore West Africa environmental conditions Spread moored FPSO Free hanging configuration HCR, SCR, flexible riser designs

SCR 4000 m long (15 deg hang-off angle) HCR & flexible 3000 m long (4 deg hang-off angle)

The HCR consists of:

Reference : DOT paper by Technip, New Orleans, November 2000

10’’ Water Injection riser 30 m of flexible pipe 2520 m of rigid pipe 450 m of flexible pipe 8” Gas Injection riser 30 m of flexible pipe 2520 m of rigid pipe 450 m of flexible pipe

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HCR vs SCR vs flexible risers study case

The HCR reduces the tensions

At the top

Simplifies the hang-off Reduces required payload capacity

• f floaters with small water crossing

areas At the bottom

Avoids the need of a riser base

anchor

Max Top Tension (te) 345 355 210 360 285 500 8" GI Riser 10" WI Riser Flexible HCR SCR Max Bottom Tension (te) 80 80 55 80 150 240 8" GI Riser 10" WI Riser Flexible HCR SCR

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HCR vs SCR vs flexible risers study case

The HCR reduces the fatigue issues in the rigid pipe

The maximum occurring stress is smaller The stress range is smaller

Max Stress Range in Rigid Pipe (MPa) 44 75 177 215 8" GI Riser 10" WI Riser Flexible HCR SCR Max Stress in Rigid Pipe (MPa) 175 300 238 417 8" GI Riser 10" WI Riser Flexible HCR SCR +117 MPa +140 MPa

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HCR vs SCR vs flexible risers study case

The HCR reduces the seabed congestion

The riser length is smaller The horizontal projection of the riser is smaller The zone in which the TDP moves is smaller

Suspended Length of pipe (m) 2860 2860 2860 2860 3580 3580 8" GI Riser 10" WI Riser Flexible HCR SCR Horizontal Projection (m) 670 670 670 670 1900 1900 8" GI Riser 10" WI Riser Flexible HCR SCR

Length of TDP Zone (m) 250 250 250 250 700 700 8" GI Riser 10" WI Riser Flexible HCR SCR

+720 m +450 m

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Contents

Flexible pipe capabilities Hybrid Catenary Riser (HCR) Free Standing Hybrid Riser (FSHR)

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Free Standing Hybrid Riser (FSHR) components

Air Can Steel Riser Taper Joint Flexible Jumper Taper / flex Joint

• Near surface top-tensioned rigid riser
• Compartmentalised air can
• Air can uplift 400 to 500 t
• Air can depth of 150 to 200 m
• Bottom connection taper joint / flex

joint

• Flexible jumper 300 to 450 m long
• Gooseneck connection at can with

bend stiffener

• Classic connection at FPU (EF / bend

stiffener)

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Free Standing Hybrid Riser (FSHR) advantages

Weight reduction at FPU Flowline / riser installation and pre-commissioning independent from FPU

arrival

Fatigue issue eliminated due to FPU motion decoupling Air can depth of 150 to 200 m wd ⇒ waves excitation mitigation Suitable for big diameter pipes Highly insulated lines (e.g. PiP) Flow assurance improvement Inspection and integrity monitoring implemented into the system design

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Free Standing Hybrid Riser (FSHR) cross section

IPB flexible jumper

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Free Standing Hybrid Riser (FSHR) fabrication &

installation

Air can

Pre-fabrication of air can in modules and testing Final air can assembly mounting prior to load out on transportation barge

Riser

J-Lay on Deep Blue

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Free Standing Hybrid Riser (FSHR) installation

Installation of jumper with standard laying vessel