Risk Based Inspection (RBI) - A Transparent Process?

Presented by:Cheryl FrolishMACAW Engineering LtdCo-Authors:Ian Diggory, Richard Elsdon, Krista McGowanMACAW Engineering LtdRichard JonesTalisman Energy (UK) Limited*

IntroductionTopsides & Pipelines RBI & Operators Integrity Management StrategyRBI Concept & SchemesTalisman RBI Process MACAW ExperienceConclusionsQuestions

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IntroductionWhy RBI?Prioritise Inspection based on the Assessment of Risk

RBI ApplicationsOil and Gas IndustryTopside ProcessesOnshore TerminalsPipeline NetworksNuclear and Aviation Applications

Core CriteriaOptimise InspectionEnsure Safe OperationProvide an Audit Trail*

IntroductionUK Regulations: Identify HazardsPreventDetectControlMitigateReduce risk as low as reasonably practicable (ALARP)

HSE Guidance:Best Practice for Risk Based Inspection as part of Plant Integrity ManagementFocuses on the form and management of RBI process rather than specific techniques or approaches*

Topsides & PipelinesTopsides RBI and subsea risk assessments share many areas of commonality, in particular:Internal corrosion risksTopside Processing can be the CAUSE of corrosion issues in your pipeline:For Example:Water CarryoverMicrobial ContaminationCondensation from Gas PhaseProcess Upsets

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Topsides & PipelinesTopsides RBI and subsea risk assessments share many areas of commonality, in particular:Internal corrosion risksTopside Processing can be the SOLUTION to corrosion issues in your pipeline:For Example:Improved Separation ProcessesInhibitor EfficiencyDew Point ControlImprove Process Reliability

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Topsides & PipelinesKnowledge of topside condition can give an early indication of potential pipeline integrity issues:

Pipework and Vessel Inspections Condition Other indications such as sand in the separators

Microbiological Surveys

Corrosion Coupons*

Topsides and Pipelines - ExampleReservoirGas PipelineOil PipelineOffshore ProcessingOnshore ProcessingCorrosion CouponWater Processing*

Topsides and Pipelines - ExampleCorrosion CouponPossible Causes: Poor separation allowing for water carryover Inhibitor partitioning time Process Upsets MIC*

Topsides and Pipelines - ExampleReservoirGas PipelineOil PipelineCorrosion CouponRBI will identify HIGH risk areas. Interaction between topside and subsea assurance teams to determine location that best represents conditions in the pipeline.The corrosion coupons have not been showing any evidence of corrosion growth. WHY? Position in the pipeLocation?Water Processing*

RBI & Operators Integrity Management StrategyMonitoring and MitigationTopside InspectionPipeline InspectionCorrosion Control StrategyRBI (Topsides)CRA, FFP & CGA (Pipeline)*ActivitiesIntegrity Schemes

RBI Concept*

IDENTIFY THREATS/HAZARDS to EQUIPMENT

(Pipework, Vessels etc)

SUSCEPTIBILITY to THREAT

MITIGATION MEASURES to REDUCE SUSCEPTIBILITY

LIKELIHOOD of FAILURE

FAILURE MODE

CONSEQUENCES of FAILURE

INSPECTION SCHEME

ASSESS INSPECTION HISTORY

IDENTIFY THREATS/HAZARDS to EQUIPMENT

(Pipework, Vessels etc)

REMAINING LIFE or INSPECTION GRADE

SUSCEPTIBILITY to THREAT

MITIGATION MEASURES to REDUCE SUSCEPTIBILITY

LIKELIHOOD of FAILURE

FAILURE MODE

CONSEQUENCES of FAILURE

ASSESS INSPECTION HISTORY

REMAINING LIFE or INSPECTION GRADE

RISK FACTOR

Internal ThreatsInternal CorrosionSweet CorrosionSour Corrosion / Cracking MechanismsMIC (Microbiologically Induced Corrosion)Oxygen CorrosionOther potential mechanisms?E.g. Acetic Acid weld degradationRef: MACAW Defect Atlas, Dr. Colin Argent*

External ThreatsExternal CorrosionAtmospheric CorrosionCUI (Corrosion Under Insulation)Chloride pitting of stainless steelsGalvanic corrosionOther potential mechanisms?Ref: HSE Offshore External Corrosion Guide*

MitigationInternalLiningsInhibitorsBiocidesH2S ScavengersO2 ScavengersGas dehydration glycol towers and mol sievesDew Point ControlMaterial typeExternalCoatingsMaterial typeEffective maintenance strategy (paint coatings and insulation cladding)

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Consequences of FailureSafetyEnvironmentProductionFluid TypeFailure ModeManning LevelsTemperature and PressureFlammabilityToxicitySize of ReleaseFluid TypeLocationTemperatureFlammabilityToxicityCommercial CriticalityBack up systems?Loss of Production*

Consequence of Failure

RBI Concept*

IDENTIFY THREATS/HAZARDS to EQUIPMENT

(Pipework, Vessels etc)

SUSCEPTIBILITY to THREAT

MITIGATION MEASURES to REDUCE SUSCEPTIBILITY

LIKELIHOOD of FAILURE

FAILURE MODE

CONSEQUENCES of FAILURE

INSPECTION SCHEME

ASSESS INSPECTION HISTORY

IDENTIFY THREATS/HAZARDS to EQUIPMENT

(Pipework, Vessels etc)

REMAINING LIFE or INSPECTION GRADE

SUSCEPTIBILITY to THREAT

MITIGATION MEASURES to REDUCE SUSCEPTIBILITY

LIKELIHOOD of FAILURE

FAILURE MODE

CONSEQUENCES of FAILURE

ASSESS INSPECTION HISTORY

REMAINING LIFE or INSPECTION GRADE

RISK FACTOR

Inspection HistoryAPI RP 570 & 510IP 12 &13 Model Code of Safe PracticeCalculate time to failure based on wall thickness measurements.

Maximum inspection interval = remaining service lifeEffectiveness and results of inspections are graded. IP guidelines set out recommended maximum intervals based on inspection gradeQuantitativeQualitative*

Inspection History

Remaining Life

Inspection Grading

Outcome of an RBI?Types of damage expectedInspection FrequencyAppropriate Inspection TechniqueHotspot locations*

What?

How?

When?

Result of an RBI

Where?

RBI SchemesIn 2002 HSE funded a study to compare several RBI schemesQuantitative vs QualitativeBlack box approachVarying levels of detailHSE study identified the need for: A TRANSPARENT processA balance between quantitative and qualitative methodsA balance between theory, inspection and engineering judgementRef: Risk Based Inspection A Case Study Evaluation of Onshore Process Plant, W Geary, 2002. *

Talisman AssetsNorth Sea Operator11 Platforms1 FPSO2 Onshore TerminalsNetwork of over 3000 km of subsea pipelinesAgeing assets, near or past design lifePrevious owners and inspection companiesIncomplete data setHistorical data often stored in hard copy onlySome existing RBI schemes but varied in type and complexityA unified approach was required*

Talisman RBI SchemeInitial Approach

Talisman had adopted an RBI programBased on API half-remaining life approachMACAWs initial role to populate and run this program

Problem

Information was limited or just not available Program required complete data set to operate successfullyA common feature of quantitative modelsGaps in inspection history and lack of confidence in results meant that API approach was not appropriate*

Talisman RBI Scheme

MACAW and Talisman collaborated in development of a more robust scheme MACAW applied the concept of transparency to Talisman RBI scheme Moved away from API approach to IP grading methodTop down approach, prioritised safety critical systems

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Talisman AssetsScale of the project:11 platforms, 1 FPSO and 2 onshore terminalsTypical platform:350 vessels (inc. heat exchangers, filters and air accumulators)3000 items of pipework (grouped into ~120 streams)For all of Talismans assets, this equates to approximately:2500 Vessel RBIs1700 Stream RBIsThe project was split into three phasesPhase 1 - Safety Critical SystemsPhases 2 & 3 Less Critical Systems*

RBI The Key StepsMACAW Team StakeholdersDefine Systems and StreamsData CollectionAssess Corrosion Threats and ConsequencesAssess Inspection HistoryReview ProcessDocumentation and HandoverTraining and Technical SupportImplementing RBIUpdating RBIsReviewing RBIs

Effective CommunicationsImplementationLive System*Define ScopeTransparent DecisionsAudit & Handover

MACAW Team

Project Manager (1)

Senior Corrosion Engineers (2)

Project Supervisors (3)

Technical Assistants (6)* Team is set up to work on 6 RBI projects at a time

Data intensive process

Engineering assessment required on missing data

Stakeholders

TalismanAssurance EngineerFocal Point EngineerProcess EngineerChemistOffshore Inspection Engineer

Inspection CompanyInspection EngineerCorrosion Engineer*

Systems and StreamsSystems are defined by their fluid and function, e.g.Produced Oil & Oil ExportGas Compression and ExportFuel GasSystems determine equipment to be assessed, such as: Separation vesselsHeat exchangers StreamsStreams are used to define sections of pipework operating under similar parameters, such as:PressureTemperatureMaterialFluid compositionAdded chemicals (e.g. Corrosion Inhibitor injection)

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Systems and StreamsProcess Flow Diagram extractBefore stream mark up

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Systems and StreamsProcess Flow Diagram extractAfter stream mark up

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Data CollectionFluid data

Design and operating details

Inspection historyCO2H2SpHWater CutMaterialWall ThicknessDesign and Operating TemperatureDesign and Operating PressureCorrosion AllowanceInternal LiningBug Count and TypeO2Sand ContentInspection TypeResults and Conclusions*

Assess Corrosion Threats and ConsequencesInternal Corrosion MechanismsSusceptibilityMitigationLikelihood of FailureExternal Corrosion MechanismsSusceptibilityMitigationLikelihood of Failure*

Assess Inspection HistoryInspection history and gradingIP 12 and 13 Inspection Grading methodModified to incorporate riskExample Pressure vessel inspections next slide

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Assess Inspection HistoryIP recommended maximum intervalRBI recommended maximum intervalNB: Hydrocarbon Systems will always fall into High and Medium Risk Categories due to the consequence of failure associated with these systems*

Review ProcessStaged Review Process

Level 1: Peer Review of each system

Level 2: Integrity Review covering all systems within each phase

Representatives required from the following areas:AssuranceInspection Process EngineeringProduction ChemistOperationsSite personnelSafety and Environment*

Documentation and HandoverDocumentation ofAssumptionsIssuesKey decisionsMarked up PFDs and P&IDsPFDs hyperlinked to RBIsReferences for Data SourcesRBIs in spreadsheet formatChange loggingLive summary sheet

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Linked PFD and RBI Front Sheet*

Risk Assessment and Data Sources

Change Log and Prompts*

Live Summary SheetACDB*

Training and Technical SupportHelpdesk set up for ongoing technical support*

Operating the SchemeOnce handed over the RBI becomes the responsibility of the clientQuality ControlsAllocated usersPermissions should be set up so that only persons who have attended training sessions may edit the RBIsProcedures for Updating and Reviewing InternallyProcedures for sharing RBI information with other interested partiesSubsea IntegrityContractors

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ConclusionsInvolve all stakeholders from the beginning of the process

Develop a system that can cope with variability of data

Decisions and criteria should be transparent

RBI is an ongoing process

The output from the RBI should carry through into pipeline integrity assessments*

Thank you for your time,any questions?*

The pipeline has just been re-inspected and a significant increase in corrosion activity has been noted. The pattern of corrosion is typical of water carryover into the pipeline (corrosion at the start of the line at the 6 oclock position) caused by poor separation. Solution: increase residence time in the separators. BUT, why did the corrosion coupons not detect the corrosion.Ref for coupon pic: NACE Technical Committee Report. 1D199 Internal corrosion monitoring of subsea production and injection systems

Of 350 vessel approx 150 will be air accumulators.Organogram or list?