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The Pipeline Integrity Management System of The Pipeline Integrity Management System of VNG Verbundnetz Gas AGVNG Verbundnetz Gas AG

Referent: Dr. Volker Busack, Operation / TechnologyReferent: Dr. Volker Busack, Operation / Technology

23. World Gas Conference,23. World Gas Conference,5th. 5th. -- 9th. June 2006, Amsterdam9th. June 2006, Amsterdam

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1.1. Introduction VNGIntroduction VNG-- VNG in the European gas transmission grid VNG in the European gas transmission grid --

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•• Length of pipelines:Length of pipelines:7,279 km7,279 km

•• Underground gas storages: Underground gas storages: 6 6 (at overall (at overall 55 sites)sites)

•• Total work gas capacity:Total work gas capacity:2.3 billion m2.3 billion m ³³

•• Compressor stations:Compressor stations:2 2 (+ 4 compressor units UGS)(+ 4 compressor units UGS)

•• Total compression capacity:Total compression capacity:77.8 MW77.8 MW ((88 piston compressors piston compressors

77 turbo compressors)turbo compressors)

•• Delivery stations / links: Delivery stations / links: 88

•• Metering and pressure Metering and pressure regulating stations: regulating stations: 3636

•• Cathodic corrosion protection Cathodic corrosion protection installations: installations: 727727

Gubin

Lasow

Bobbau

Kamminke

1.1. Introduction VNGIntroduction VNG-- Technical infrastructure at VNG Technical infrastructure at VNG --

supply area: 108,000 kmsupply area: 108,000 km ²²

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Reserve in the bearing capacityReserve in the bearing capacityof a highof a high --pressure gas pipelinepressure gas pipeline

2.2. Changes in pipeline statusChanges in pipeline status-- Pipeline quality curve Pipeline quality curve --

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Specific aims of Specific aims of PIMSPIMS at VNG at VNG -- Verbundnetz Gas AG:Verbundnetz Gas AG:

•• Evaluation of results of inspection pigging by neuro nal networksEvaluation of results of inspection pigging by neuro nal networks(FEM), incl. corrosion forecast with assessment program (FEM), incl. corrosion forecast with assessment program ““ COPCOP””(Corrosion On Pipelines)(Corrosion On Pipelines)

•• Technical condition analysis of pipelines by probabi listic Technical condition analysis of pipelines by probabi listic assessment criteria / parametersassessment criteria / parameters

•• Evaluation of possible service lifeEvaluation of possible service life

•• Identification of failures / weak spots with followi ng prioritizIdentification of failures / weak spots with followi ng prioritiz ation ation of needed actions / measuresof needed actions / measures

•• Optimization and Processing of needed rehabilitation m easuresOptimization and Processing of needed rehabilitation m easures

•• Data management and providing a pipeline information systemData management and providing a pipeline information system

3.3. Aims, elements and methods of PIMSAims, elements and methods of PIMS-- Aims and requirements Aims and requirements --

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Pre

ssur

eP

ress

ure

TCA Assessment of technical conditionTCA Assessment of technical condition

SRASRA Structural Reliability AnalysisStructural Reliability Analysis

Reliability analysisReliability analysis

Limit value balancingLimit value balancing

Detection of system flawsDetection of system flaws

Rehabilitation controlRehabilitation controlProof of integrityProof of integrity

Population densityPopulation density

QRAQRAQuantitative RiskQuantitative Risk

AnalysisAnalysis

QuantitativeQuantitative

risk analysisrisk analysis

PermissionPermission

How failure occurredHow failure occurred

Tra

ffic

Tra

ffic

Soi

lS

oil

Cor

rosi

onC

orro

sion

Def

ect

Def

ect

stat

istic

sst

atis

tics

PfPf 11 PfPf 22 PfPf 33 PfPf 44 PfPf 55 PfPf ii PfPf jj

. . . . . . . . . .

CalculateCalculate

failure probabilityfailure probability

Link PfLink Pf ii

Calculate effectCalculate effect

Individual risk,Individual risk,

General riskGeneral risk

. . . . . . . . . .

3.3. Aims, elements and methods of PIMSAims, elements and methods of PIMS-- Pipeline failure probability, QRA and SRA Pipeline failure probability, QRA and SRA --

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Risk

10-3/a

10-4/a

10-5/a

10-6/a

not acceptable

alarming

acceptable to staff

acceptable to general

public

10-7/a

Remarks

too high: major improvements reqd.

very high: look for alternatives/

major improvements

high: find improvements

low: find most economical

solution

negligible: take normal

precautions

3.3. Aims, elements and methods of PIMSAims, elements and methods of PIMS-- Risk triangle Risk triangle --

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3.3. Aims, elements and methods of PIMSAims, elements and methods of PIMS-- PIMS elements at VNG PIMS elements at VNG --

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•• Methods and techniques for pipeline assessment / ins pection:Methods and techniques for pipeline assessment / ins pection:

•• Pipeline Integrity Management System (PIMS)Pipeline Integrity Management System (PIMS)

•• Technical Condition Analysis (TCA)Technical Condition Analysis (TCA)

�������� specific specific expert systemsexpert systems

•• Intelligent / Inspection piggingIntelligent / Inspection pigging

•• Program Program ““ KaRoKaRo ”” for corrosion assessment / forecastingfor corrosion assessment / forecasting

•• Program Program ““ FADFAD”” for evaluation of old welding seamsfor evaluation of old welding seams

•• Cathodic corrosion protection Cathodic corrosion protection ““ CCPCCP””

3.3. Aims, elements and methods of PIMSAims, elements and methods of PIMS-- Modern and efficient methods of PIMS Modern and efficient methods of PIMS --

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Technical Condition Analysis Technical Condition Analysis for highfor high --pressure gas pipelinespressure gas pipelines

Piggable pipelines: 4,121 kmPiggable pipelines: 4,121 km

Inspection PigsInspection Pigs

-- Assess wall thickness deterioration Assess wall thickness deterioration using Finite Element Method (FEM) using Finite Element Method (FEM)

-- For calculation use neural networks For calculation use neural networks with KaRo (pipeline corrosion) with KaRo (pipeline corrosion) programprogram

-- Estimate remaining service life by Estimate remaining service life by making corrosion forecastmaking corrosion forecast

NonNon --piggable pipelines: 3,195 kmpiggable pipelines: 3,195 km

TCATCA

-- Assess Assess linear section (linear section ( pipeline data, pipeline data, ambient conditions, etc.) and specific ambient conditions, etc.) and specific featuresfeatures (valves, fittings, special (valves, fittings, special structures, etc.) acc. to probabilistic structures, etc.) acc. to probabilistic criteria (failure probability)criteria (failure probability)

-- Prioritize weak pointsPrioritize weak points

Identify immediate steps, derive multiIdentify immediate steps, derive multi --stage plan for weak point stage plan for weak point rehabilitationrehabilitation

4.4. TCA and Inspection piggingTCA and Inspection pigging-- Technical condition analysis TCA Technical condition analysis TCA --

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5.5. Content and results of TCAContent and results of TCA-- List of raw data List of raw data –– Selection of parameters Selection of parameters --

Priority: must (1)Priority: must (1)11 Year of constructionYear of construction

22 CulvertCulvert

33 DiameterDiameter

44 Casing pipeCasing pipe

Priority: shouldPriority: should

55 Design pressureDesign pressure11 Pipeline construction details (Bends etc.)Pipeline construction details (Bends etc.)

66 Settling pressuresSettling pressures22 Cathodic Corrosion ProtectionCathodic Corrosion Protection

77 CoverageCoverage33 Pigging dataPigging data

88 Wall thicknessWall thickness44 DamagesDamages

55 RepairsRepairs

Priority: must (2)Priority: must (2) ......

11 AsAs--built quality, built quality, ZfPZfP--testtest

22 Operating pressureOperating pressure

33 Empirical values at pipeline, damage statisticsEmpirical values at pipeline, damage statistics

Priority: canPriority: can

44 Above ground pipelineAbove ground pipeline11 CoatingCoating

55 SlopeSlope22 GroundwaterGroundwater

66 MediumMedium33 Ground utilizationGround utilization

77 Proximity seam of a secure connectionProximity seam of a secure connection44 Dynamic stressesDynamic stresses

88 Insufficient distance from structureInsufficient distance from structure55 Soil aggressivenessSoil aggressiveness

99 Type of seamType of seam66 Electrical external voltageElectrical external voltage

1010 Seam fracture on this pipelineSeam fracture on this pipeline......

1111 HollowHollow

1212 Mining pressuresMining pressures

1313 TemperatureTemperature

Priority: InformationPriority: Information

1414 Type of connectionType of connection

11 ManufacturerManufacturer

1515 Traffic route (rail, road)Traffic route (rail, road)

22 DocumentationDocumentation

1616 MaterialMaterial

......

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Exemplary result Exemplary result of pipeline of pipeline

characteristicscharacteristics

5.5. Content and results of TCAContent and results of TCA-- Example for pipeline assessment (I) Example for pipeline assessment (I) --

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1,00E-20

1,00E-19

1,00E-18

1,00E-17

1,00E-16

1,00E-15

1,00E-14

1,00E-13

1,00E-12

1,00E-11

1,00E-10

1,00E-09

1,00E-08

1,00E-07

1,00E-06

1,00E-05

1,00E-04

1,00E-03

1,00E-02

55000 55500 56000 56500 57000 57500 58000 58500 59000 59500 60000

Metre of pipeline

Pro

babi

lity

of fa

ilure

1 2

66

8

13

16

3

4

5

7

11

12

9 10

14 15

Limit

Exemplary result for design pressure PN 25 barExemplary result for design pressure PN 25 bar

5.5. Content and results of TCAContent and results of TCA-- Example for pipeline assessment (II) Example for pipeline assessment (II) --

Crossing with traffic Crossing with traffic route, casing piperoute, casing pipe

Crossing with traffic Crossing with traffic route, casing piperoute, casing pipe

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KaRo assessment programKaRo assessment program

Evaluate large data quantitiesEvaluate large data quantitiesfrom inspection pigging:from inspection pigging:

•• Assess / classifyAssess / classifydefective placesdefective places

•• Derive immediate stepsDerive immediate steps(e.g. safeguarding program,(e.g. safeguarding program,pressure reduction)pressure reduction)

Assess local defects (digging):Assess local defects (digging):

•• Determine defect parametersDetermine defect parameters(wall thickness reductions) on site (length, width, depth)(wall thickness reductions) on site (length, width, depth)

•• Recalculate operating pressure, identify repair methodRecalculate operating pressure, identify repair method

KaRoKaRo -- program for corrosion assessmentprogram for corrosion assessment

6.6. Selected methods and toolsSelected methods and tools-- KaRo KaRo -- Corrosion of pipelines Corrosion of pipelines --

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Aims: Aims:

•• Determine remaining operation life for wall thickness Determine remaining operation life for wall thickness

deteriorationdeterioration

•• Optimize repair time / method (avoiding supply interrupt ion, Optimize repair time / method (avoiding supply interrupt ion,

e.g. by field coating, clock spring, collars, etc.)e.g. by field coating, clock spring, collars, etc.)

•• Plan repeat inspection pigsPlan repeat inspection pigs

Applications:Applications:

•• Wall thickness deterioration requiring no immediate rep air Wall thickness deterioration requiring no immediate rep air

and for which the effectiveness of cathodic protecti on has and for which the effectiveness of cathodic protecti on has

not been provennot been proven

Corrosion forecastCorrosion forecast

6.6. Selected methods and toolsSelected methods and tools-- Corrosion forecast Corrosion forecast --

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Surface scanSurface scan FE result FE result

6. 6. Selected methods and toolsSelected methods and tools-- FE Modelling of corrosion areas FE Modelling of corrosion areas --

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7.7. Process steps of PIMSProcess steps of PIMS

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•• Using the TCA method since 1998 within the scope of PIMSUsing the TCA method since 1998 within the scope of PIMS

•• up to now approx. 3,000 km of highup to now approx. 3,000 km of high --pressure pipelines assessed pressure pipelines assessed

in detail and rehabilitation measures classified int o priority sin detail and rehabilitation measures classified int o priority s tages tages

1 1 -- 3 (defined levels)3 (defined levels)

•• Results of rehabilitation processing in reference to realistic Results of rehabilitation processing in reference to realistic

conditions optimally suitable for verifyingconditions optimally suitable for verifying

•• Advantages:Advantages: -- Planning reliability / safetyPlanning reliability / safety

-- cost lowering / optimizationcost lowering / optimization

-- proof of reliability and technical integrityproof of reliability and technical integrity

8.8. ConclusionsConclusions