integrity management of submarine pipeline systems - ptil.no rledninger... · pdf file-...

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)


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


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


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.


The Integrity Management (IM) System

SurroundingFacility Systems

The Core


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:


• 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


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


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


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


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


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


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


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


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


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


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


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.


Safeguarding life, property and the environment

www.dnv.com

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