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Pipeline DesignCritical Factors and The Impact on
Pipeline Repair Feasibility
SPE Workshop Abu DhabiJanuary 2009
Roland Palmer-JonesPenspen Integrity, UK
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Penspen Integrity“Know and Manage your Pipeline Risk”
Penspen Integrity is an independent specialist pipeline engineering consultancy. We provide services including:
Integrity managementDefect assessmentRisk analysisCorrosionCathodic protection (CP) advice and field support, Pigging consultancySmart pig data analysisDirect assessmentTrainingResearch
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Pipeline Design
DriversCostSchedule
Issues CoveredRoute + Shore Approaches Hydraulics – Diameter and PressureMaterialsConfigurationConstructionStrength – Wall thicknessStability, Buckling, SpansFittings (flanges, valves, pig traps etc.)
Design HAZID
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Route
Steep SlopesDifficult to work
Deep WaterDiverless systems
BurialExcavation required
Access problemse.g. Sand waves
30 degree slopes
sand waves
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MaterialsHigh Toughness / Good Ductility
Prevents running fractureCorrosion control by CRA liner
Clamps will not workSpecial connectors required
FlexiblesDifferent problems
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Configuration
HPHT – Snake Lay Repair may introduce local restraint
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Fittings
FlangesEase section replacementPotential source of leaks
ValvesAllow isolation
Pig trapsEnable the deployment of isolation tools
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Spare Pipe
Minimum 3 pipe lengthsMay be 1 to 2% of total length
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Design HAZID
Identify the Hazards Identify Potential DamageIdentify Suitable Repairs
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Hazard Data UK North Sea
Causes of Incidents to Operating Steel Pipelines
0102030405060
Ancho
rIm
pact
Corros
ionStru
ctural
Materia
lNat.
Haz
ard
Fire/Exp
losion
Constr
uctio
nMain
tenan
ceHum
an Erro
r
OP. Prob
lems
Other
Cause
No.
of I
ncid
ents
OtherPipelineSafety ZoneRiserPlatform
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Hazard - Internal Corrosion
DamageDeep pitsCrackingLeaks
RepairClamp - temporary solutionCorrosion must be controlledReplacement
1 3 5 7 9
11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
S1
S6
S11
S16S21
S26S31
20
22
24
26
28
30
32
34
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Hazard – Anchor Damage
Damage Dent, Gouge, Bending, Rupture
RepairGrouted sleeveSection replacement
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Hazard – sea bed movement
Damage –Bending strainsCollapseRupture
RepairExcavation Replacement
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Hazard - Spanning
DamageFatigue cracking, Rupture.
Repair Span supportStructural ClampReplacement
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Summary
Pipeline design is generally not influenced by repairSlopesHPHT – snake layBundlesFlexibles
The design HAZID provides an opportunity to identify hazards, damage and repair options.
