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PSA Stavanger 9 December 2009
Integrity Management of Submarine Pipeline SystemsB.H.Leinum, Det Norske Veritas
© Det Norske Veritas AS. All rights reserved. 2
Presentation - Content
Introduction to DNV RP-F116 on Integrity Management of Submarine Pipeline System
Examples from the IM-process for the Siri Infield-Pipelines in Danish Sector (Dong Energy)
© Det Norske Veritas AS. All rights reserved. 3
DNV RP-F116; Motivation & State-of -AffairMotivation:- Feedback from industry- Aging pipeline systems - Life time extension and re-qualification of existing pipelines - Optimised design imply stricter need for monitoring- Novel design gives new challenges
State-of-affairAs pr. today, there are no recognized specifications or recommended practices available covering subsea integrity management systems
- API1160 “Managing System Integrity for Hazardous Liquid Pipelines”
- ASME B31.8S “Managing System Integrity of Gas Pipelines”
Objective:- Address in-service issues of concern from early design
phase and through the operational phase- Compile best industry practice and sound engineering
practice for how to establish and maintain the integrity of subsea pipeline systems
Onshore Codes
© Det Norske Veritas AS. All rights reserved. 4
Recommended practice for IM of Submarine Pipeline Systems
JIP Participants shows international co-operation;
CNOOC
DONG Energy
ENI Group
Gassco
Gaz de France
Statoil
SINTEF
Norske Shell
DNV
© Det Norske Veritas AS. All rights reserved. 5
What is Pipeline System Integrity?
There are two main failure modes related to the pipeline’s containment / structural function:
The function of pipeline systems is to efficiently and safely transport a variety of fluids
Pipeline system integrity is defined as the pipeline system’s structural/containment function. It is the submarine pipeline system’s ability to operate safely and withstand the loads imposed during the pipeline lifecycle. If a system loses this ability, a failure has occurred.
- Loss of containment – leakage or full bore rupture. - Gross deformation of the pipe cross section resultingin either reduced static strength or fatigue strength.
© Det Norske Veritas AS. All rights reserved. 6
The Integrity Management (IM) System
SurroundingFacility Systems
The Core
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Integrity Management (IM) Process
Pipeline integrity is
Established during the concept, design and construction phases.
Maintained in the operations phase.
Transferred from the development phase to the operations phase. This interface involves transfer of vital data and information about the system.
IM-Process in a life cycle perspective:
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• DFI threats → Material– Material related– Manufacturing related– Fabrication related– Installation related– Design errors
• Corrosion/erosion → Corrosion– Internal corrosion– External corrosion– Erosion
• 3rd party threats → Impact & Anchor– Trawl interference– Anchoring– Vessel impact– Dropped objects
• Structural threats → Structural– Global buckling – exposed line– Global buckling – buried line– End expansion– On bottom stability– Static overload– Fatigue
• Natural hazard threats → Natural Hazard– Extreme whether– Earthquake– Landslide– Ice loads
• Incorrect operation → Other +– Incorrect procedures– Procedures not implemented– Human errors
Threat group versus failure statistics
8
Anchor18 %
Impact24 %
Corrosion27 %
Structural5 %
Material10 %
Other11 %
Nat. Hazard5 %
The North Sea*All reported incidents, both leakage and not leakage
* Fittings are not included
© Det Norske Veritas AS. All rights reserved. 9
Risk Assessment & Integrity Mangment PlanningA) Equipment scope
B) Identify threats
C) Data gathering
D) Data quality review
Data OK?
F) Estimate CoF E) Estimate PoF
G) Risk = PoF x CoF
Risk OK
I) All equip./threats considered?
J) Aggregated risk
Risk OK
K) IM Planning
No
Yes
Yes No
H) Mitigation
Yes
Yes
No
No
No
Risk assessment and IM Planning – main tasks and link to code requirements (DNV-OS-F101):
Define equipment scope ( i.e. all equipment that can lead to a failure)
For each equipment, identify all threats which can lead to a failure
For each threat; estimate risk - Consequence of failure (CoF)- Probability of failure (PoF)
Propose plans for:- Inspection, monitoring and testing (IMT) - Mitigation, intervention and repair (MIR) - Integrity assessment (IA)
Risk assessment – working process
© Det Norske Veritas AS. All rights reserved. 10
Example: The Danish Oil and Natural Gas system – Siri Field
Nini
Cecilie
Siri
10" Water injection
10" Water injection4" Gas lift
4" Gas lift
3” Gas lift
13 km
32 km
9 km
SCB-2 Water injection
8” Multiphase
12" Multiphase
14" MultiphaseStine S1Production SCB-1
16" OilOil Storage tank
Umbilical
SAL System
Nini
Cecilie
Siri
10" Water injection
10" Water injection4" Gas lift
4" Gas lift
3” Gas lift
13 km
32 km
9 km
SCB-2 Water injection
8” Multiphase
12" Multiphase
14" MultiphaseStine S1Production SCB-1
16" OilOil Storage tank
Umbilical
SAL System
Location Type of Pipeline
Size Length [km] Pigging Facilities Inst. year
Design life,years
Notes
1 Nini - Siri MP 14” 31.7 Cleaning & ILI 2003 152 Nini - Siri WI 10” 31.7 Cleaning & ILI 2003
15 Piggy-back3 Nini - Siri GL 4” 31.7 2003
4 Cecilie - Siri MP 12” 12.9 Cleaning & ILI 2003 15
5 Cecilie - Siri WI 10” 12.9 Cleaning & ILI 200315 Piggy-back6 Cecilie - Siri GL 4” 12.9 2003
7 Stine 1 - Siri MP 8” 8.9 Emergency 200312 Piggy-back8 Stine 1 - Siri GL 3” 8.9 Emergency 2003
9 Siri/Nini - SCB2 WI 6” None 2003 12 10”x6” tee spool
The Siri-Nini-Cecilie-Stine Field
© Det Norske Veritas AS. All rights reserved. 11
Risk based approach; Basis for the inspection plan
1. Identification of threatsMajor threats; Third Party interference (impact) and Corrosion (internal/external).
2. Risk Assessment
3. Identification of regulatory requirement
4. Selection of inspection methods (how)
5. Inspection scheduling (where, when and what)
6. Integrity Assessment
© Det Norske Veritas AS. All rights reserved. 12
Example of a Risk assessment scheme
Threat Group Threat PotentialInitiator
PipelineSections
Protective means(DFI)
AcceptanceCriteria
PoF Category
CoF Category
Risk Category
Additionalprotective means IMT Activities IMT frequency
Design errorsFabrication defectsInstallation related Internal corrosionExternal corrosionErosionTrawling interference AnchoringVessel impactDropped objectsVandalism / terrorismOther mechanical impact Global buckling – exposedGlobal buckling – buriedEnd expansionOn-bottom stabilityStatic overloadFatigueExtreme weatherEarthquakesLandslidesIce loadsSignificant temperature variationsFloodsLightningIncorrect proceduresProcedures not implementedHuman errorsInternal Protection System RelatedInterface component related
Initial risk assessment Inspection planningThreat identification; date gathering and design review
Corrosion / Erosion
DFI
Normally covered by other supporting elements (e.g. audits and review, i.e.
operating in compliance with operatinal controls and procedures)
Normally covered through QA/QC during DFI
Normally covered by monitoring activities and after "unplanned event" inspection
(not part of the long term inspection program)
Third Party
Structural
NaturalHazard
Incorrect Operation
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All pipelines were screened and categorised for risk of internal corrosion
Following definitions were used:- Insignificant – Condition assessed as better than design- Moderate – According to Design- Significant – Corrosion allowance consumed before end design life- Severe – Corrosion allowance consumed before end design life or
non-quantifiable corrosion rate
Expected development was predicted using NORSOK M-506 for determing corrosion rates.
Internal threat screening - corrosion
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Based on DNV RP-F101, "Single defect" methodology.
From in-line inspection performed by Ultra Sonic pig (10" WI Riser showed on figure).
Integrity Assessment: Pipeline burst capacity calculation
Detailed inspection data - Allowable measured defect size for 247bar
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700 800Defect length (mm)
Rel
ativ
e de
fect
dep
th (d
/t)
Allow able defect size
Features
© Det Norske Veritas AS. All rights reserved. 15
Suggested programme for WI-lines
Requirement for internal monitoring and control programme
Monitoring parameter Schedule Seawater Produced water
Pressure, temperature, flow rate On-line X X
Chemical injections Continuously X (scale inhibitor) X (scale/corrosion inhibitor)
O2-content On-line X NA
CO2, H2S Regularly NA X (in degasser)
Bacteria Regularly XRegularly (in seawater system)
Xseawater system, process top side Siri and at Cecilie and Nini WHP, if possible
Residual bactericide at the end of the pipeline
In connection with bactericide treatments
X X
Injection water chemistry of producers (especially Ba, Sr, SO4
2-)X(monitor seawater breakthrough)
X
Suspended solids Regularly X X
Residual inhibitor Regularly X (scale inhibitor)
X (corrosion and scale inhibitor)
Residual scavenger Regularly X (oxygen scavenger)
Residual chlorine Regularly X
© Det Norske Veritas AS. All rights reserved. 16
Main groups- DFI – Threats related to design, fabrication and installation- Third party – Damage to the pipeline caused by third party interference, e.g. anchor or trawl
impact- Structural – Damage to the pipeline caused by buckling, static over loading, fatigue etc.
A high level assessment of the Estimate probability of failure (PoF)
Estimate consequences of failure (CoF)
Determine risk- Since the pipelines in question were all buried, most of the threats were screened out. However, there
were two threats that possibly could impact the structural integrity of the pipeline;- Anchor hooking- Upheaval buckling
To evaluate the risk areas of above threats, an identification of previously performed surveys was needed.
External threats screening
© Det Norske Veritas AS. All rights reserved. 17
Integrity Assessment in General (DNV RP-F116)Overview of damages/anomalies vs. assessment codes
Flow diagram illustrating the different activities the integrity assessment process consists of
© Det Norske Veritas AS. All rights reserved. 18
Based on the performed assessment, a 5-year inspection program was proposed.
Establishment of a Long Term Inspection plan
Siri interfield - Inspection Program 2008-2013* = Recommended scheduled inspection Inspection types:* = Scheduled inspection not performed* = Inspection performed but no evaluation of results* = Inspection and evaluation performed
AC ROV ILI AC ROV ILI AC ROV ILI AC ROV ILI AC ROV ILI AC ROV ILINiniNini-Siri 4" GL pipeline * R+PT R+SA * R+SA R+SA * R+SANini-Siri 10" WI pipeline Pipeline to be replaced R R+PT * R+SA * R+SA * R+SANini-Siri 14" MP pipeline * * R+PT R+SA * R+SA R+SA * R+SA
CecilieCecilie-Siri 4" GL pipeline * R+PT R+SA * R+SA R+SA * R+SACecilie-Siri 10" WI pipeline * * R+PT R+SA * R+SA * R+SA * R+SACecilie-Siri 12" MP pipeline * * R+PT R+SA * R+SA R+SA * R+SA
StineStine-Siri 3" GL pipeline * * R+PT R+SA * R+SA R+SA * R+SAStine-Siri 8" MF pipeline * * R+PT R+SA * R+SA R+SA * R+SA6"x10" WI tee-spool * * PT R+SA * R+SA R+SA * R+SA
2012 20132008 2009 2010 2011
AC: Acoustic Survey, * = entire pipelineROV: Rov Inspection, R = Riser(s), PT = Pipe tracker, SA = Selected AreasILI: In-Line Inspection
© Det Norske Veritas AS. All rights reserved. 19
SUMMARYNew RP-F116 gives requirements and recommendations for the development of a guideline on integrity management system of submarine pipeline systems from the conceptual design and during operation
Underlines the importance of transfer of integrity from conceptual/design phase to the operational phase
Recommendations related to global buckling, corrosion monitoringparameters, overview of common pipeline threats,risk assessment schemes and an example on riskassessment and IM planning
Experience has shown that documentation and structured chart of responsibilities is important to ensure that the pipeline is operated according to the premise made in design.
© Det Norske Veritas AS. All rights reserved. 20
Safeguarding life, property and the environment
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