Hthp Expansion - Jpk

8/11/2019 Hthp Expansion - Jpk

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Design Solutions for

Reducing End Expansion

Use Pipe in Pipe

Increase Spool Capacity

Increase Axial Friction Trench and Bury

Site specific pipe-soil Geotechnical Investigation

Weight Coating

Spot rock dump / mattresses Fins/ Strakes/Spiders

Pipe Anchors

Lateral Buckling

Snake Lay

Buckle Initiator

Sleepers

Buoyancy


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Pipe in Pipe

Pros:

Proven technology

Insulation can be included

Provides physical protection Can be snaked laid

Less prone to pipe walking

Suited to deep and shallow water

Cons:

Increased pipe weight

Complex field joints

Reduced lay rate

Cost:

Cost of pipe in pipe is high due to cost of outer pipe andreduced lay rate.


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Typical Expansion Movements

For Pipe in Pipe and Single Pipe

0

2

4

6

8

10

12

100 60 30

Operating Temperature (C)

PipelineEnd

Expansion(m)

Single Pipe, 0.3 friction


PIP, 0.3 friction

PIP, 0.6 friction


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Typical Anchor Lengths

For Pipe in Pipe and Single Pipe

0

5

10

15

20

25

100 60 30

Operating Temperature (C)

PipelineAnch

orLength(km)



PIP, 0.3 frictionPIP, 0.6 friction


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Increase Spool / Jumper Expansion Capacity

Pros:

Proven technology

Limit state methods can be used

Cons:

Connector capacities limited

Expansion exceeds possible spool capacity

Time needed to develop new connectors

Cost:

Cost of longer spools is low

Cost of developing new connectors is high


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Increase Axial Friction

Trench and Bury

Pros:

Will reduce pipeline expansion

Cons:

Deep water trenching is difficult

Cannot inspect the pipeline once it is buried

Susceptibility to upheaval buckling

Prohibitive cost of deep water trenching spread Increased temperature due to insulating effect of

backfill

Uncertainty over backfill geotechnical properties

Cost: Cost of trenching is high due to spread costs.


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Site specific pipe-soil Geotechnical Investigation

Pros:

Improved confidence in friction factors

Makes design of lateral buckling based solution

easier

Cons:

Time required to collect and interpret data

Cost:

Cost of gathering site specific data is low due tomarginal vessel and equipment cost


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Weight Coating

Pros:

Will reduce end expansions Will help guarantee controlled buckles occur

Will reduce feed-in to buckles

Cons:

Increased likelihood of uncontrolled lateral buckling due

to higher axial forces Increased lateral friction factors will result in higher

strains at buckle locations

Difficulty in installing weight-coated pipelines

Cost: Cost of concrete coating or clump weights is medium


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Spot rock dump / mattresses

Pros:

Can reduce end expansions Can help guarantee controlled buckles occur

Can reduce feed-in to buckles

Can eliminate potential for uncontrolled buckles

Cons: Large quantities of rock required to counter settlement

Increased installation time and cost (especially for

mattresses)

Specialist vessels required (deepwater fall pipe)Cost:

Cost of rock dumping is high due to spread costs


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Fins/Strakes/Spiders

Pros:

Embedment can mobilise additional soil friction

Cons:

Units have to be suitable for deployment over

lay barge stinger

Limited track record

Cost:

Cost of fins is medium assuming no delay in

pipe lay.


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Pipe Anchors

Pros:

Anchors are being proposed to prevent pipewalking in deepwater

Cons:

Limited track record

High anchor loads

Anchors will be large and heavy

Subsea connection of anchor to pipeline hard toachieve

Fishing interaction in shallow water

Cost: Cost of anchors is high due to fabrication cost and

installation cost


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Lateral Buckling

Snake Lay

Pros:

Proven track record in shallow water

Cons:

Difficult to achieve tight lay radii in deepwater

Insufficient axial friction to guarantee buckle initiation Uncertainty over soil-pipe interaction in soft soils

Lateral buckles may overstress pipeline

Cost: Cost of snake lay is medium associated with

engineering and slightly longer pipe length.


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Pipe in Pipe Snaked Lay

Penguin Production Line

Shell North Sea

34 Bends

28 Buckle Sites


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Pipeline Snake Geometry


Pipelay Shape to

Approx. Scale


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Operational Feedback

Feed-Back

Operation

First Oil 4/1/2003

3 months - high spec survey

All Buckle Sites Formed

80 bara, 93 C at DC5

2 Short Sections Buckled?

Video Record along routeBoulders swept away

9 months - high spec survey

Satisfactory

Shutdown for Brent Safety

Late September 2003

Started Up again last week


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Installer Feedback

Feedback

InstallationSaipem - Castoro Sei

ROV Touch down Monitoring

ROV moved some boulders

As-installed survey

Buckle Sites ~ 1500m Rad+/- 2m of target laydown

No embedded boulders


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SPD 4

Phase 1

PLEM 2

PLEM 1

Phases 2 & 3

SPD7

SPD8

SPD9

South Pars Development

Field Layout

SP6-1

&2

SP7-

1&2

SP8

-1&2

80m

80m

Phase 6, 7 & 8

pipelines

Condensate line

N

SPD 3

Phases 4 & 5

3 identical NNM wellhead platforms

Transporting 3-phase wet gas toshore

Via 3, 110km long, subsea 32trunklines

Each with a 4 MEG injectionpiggyback line.

Single Line Snaked Lay

South Parrs Trunklines


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Pipeline Route Length = 110km

Platform

(KP 110)

Shore

(KP0.0)KP80

Rough Seabed

KP50

Snaked Lay

KP30

Free Span

Feed-in

Below Critical

Buckling Limit

Pipeline Temperature Profile 4C89C


South Parrs

Route Length Buckling Mitigation


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South Parrs

Nested Snaked Lay Pipeline Routes and Buckle Sites


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South Parrs

Snaked Lay Pre-Buckle Shapes


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South Parrs

Buckle Formations Approaching Platforms

40 x Magn i f i ca t i on o f l a te ra l d i sp lacem en ts a long the SP6 , 7 and 8 p ipe l i nes

2,945,000

2,950,000

2,955,000

2,960,000

2,965,000

2,970,000

2,975,000

618,000 620,000 622,000 624 ,000 626,000 628,000 630,000 632,000 634,000 636,000

E a s t in g s ( m )

Northings(m)

50 concrete wt coat

Extg pipeline

70 concrete weight coat

Platform

Extg SP2

pipeline

Extg SP3

pipeline

SPD 9(KP110.5)

SPD 7

(KP95.4)

SPD 8

(KP101.8)

KP80

KP88


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South Parrs

3D Image of Snaked Lay Pipeline Route


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12 by 23km stainless steel pipeline

Reeled installation

Flow assurance for 95 deg C inlet

7 lateral buckle sites

Single layer insulation

Friction sensitivity studies

Ratcheting,fatigue, creep and buckle interaction code checks

Strain based acceptance criteria

Shell International verification

Single Line Buckle Initiator

Echo Yodel Flowline

Woodside Energy - West Australia


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Single Line Buckle Init iator

Echo Yodel

Pipeline Route


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Echo Yodal

Buckle Init iator Geometry

Perodic Lateral Buc kl ing Init iat ion Feature (1000m Radius o f Curvature)

0

2

4

6

8

10

12

14

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800

Distance (m)

Amplitud

e(m)

1000m Radius

IP2 (411.521, 13.700)

2000m

Radius

2000m

Radius

375.0m IP2 to IP3375.0m IP1 to IP2

IP1 (36.521,0.0) IP3 (786.521, 0.0)


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Echo Yodel

As Built Survey


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Echo Yodel

Operational Lateral Buckling


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Lateral Buckling

Lay Over Sleepers

Pros:

Proven technology in deepwater and shallow water

Better control on how the pipeline buckles than snake layonly

Hybrid designs available

Cons:

Bearing design of sleepers for low strength soils Insufficient axial friction to guarantee buckle initiation.

Fatigue in spans induced by sleepers

Buckles may overstress pipeline

Interaction with fishing in shallow waterCost:

Cost is high due to fabrication and deployment of sleepers


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Lateral Buckling

Post buckle survey profile for a 14-inch CRA pipe (long trigger)

L l B kli


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Lateral Buckling

Post Buckle Survey Profile for a 24-inch CRA Pipe

(Short Trigger)

L t l


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Pipe in Pipe

Sleepers

Lateral

Buckling

Sleepers

L t l B kli


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Lateral Buckling

Lay Over Sleepers

Water Injection Lateral Buckling Analysis

Lateral Buckling


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Lateral Buckling

Lay Over Sleepers

Water Injection Lateral Buckling Results

DNV Utili ty Check for i75 Route (Sensi tivity)

0.2

0.4

0.6

0.8

1.0

1.2

0 5000 10000 15000 2000

KP (m)

DNVUtility

High FrictionHigh Lateral Low AxialLow FrictionLow Lateral High Axial

Lateral Buckling


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Lateral Buckling

Lay Over Sleepers

Water Injection Expansion Results

PIPELINE DESCRIPTION NO INITIATORS WITH INITIATORS

Hot End - FLET 3.4 2.0

ITA 0.6 0.6I65Cold End - FLET 0.6 0.6


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Lateral Buckling

Layover Sleeper with Trigger


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Lateral Buckling

Buoyancy

Pros:

Better control on how the pipeline buckles thansnake lay only.

Cons: Not proven technology

Difficulty passing buoyancy though lay bargefiring line

Insufficient axial friction to guarantee buckle

initiation. Fatigue in spans induced by buoyancy

Buckles may overstress pipeline

Interaction with fishing in shallow water

Cost: Cost is medium due to fabrication and attachment

of buoyancy


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Key Findings

A range of design solutions exist for reducing HT expansion movements

Low cost solutions include

Increase Spool Capacity proven Site specific pipe-soil Geotechnical Investigation proven

Medium cost solutions include

Snake Lay - proven

Buckle Initiator - proven Weight Coating - proven

Fins/Strakes/Spiders limited experience

Buoyancy limited experience

High cost solutions include

Use Pipe in Pipe - proven Trench and Bury - proven

Spot rock dump / mattresses limited experience

Sleepers - proven

Pipe Anchors limited experience


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Hthp Expansion - Jpk

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