Risk Based Inspection (RBI) - A Transparent Process?

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Risk Based Inspection (RBI)
- A Transparent Process?

• Presented by Cheryl Frolish
• MACAW Engineering Ltd
• Co-Authors Ian Diggory, Richard Elsdon, Krista
  McGowan MACAW Engineering Ltd
• Richard Jones Talisman Energy (UK) Limited

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• Introduction
• Topsides Pipelines
• RBI Operators Integrity Management Strategy
• RBI Concept Schemes
• Talisman RBI Process MACAW Experience
• Conclusions
• Questions

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Introduction

• Why RBI?
• Prioritise Inspection based on the Assessment of
  Risk
• RBI Applications
• Oil and Gas Industry
• Topside Processes
• Onshore Terminals
• Pipeline Networks
• Nuclear and Aviation Applications
• Core Criteria
• Optimise Inspection
• Ensure Safe Operation
• Provide an Audit Trail

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Introduction

• UK Regulations
• Identify Hazards
• Prevent
• Detect
• Control
• Mitigate
• Reduce risk as low as reasonably practicable
  (ALARP)
• HSE Guidance
• Best Practice for Risk Based Inspection as part
  of Plant Integrity Management
• Focuses on the form and management of RBI
  process rather than specific techniques or
  approaches

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Topsides Pipelines

• Topsides RBI and subsea risk assessments share
  many areas of commonality, in particular
• Internal corrosion risks
• Topside Processing can be the CAUSE of corrosion
  issues in your pipeline
• For Example
• Water Carryover
• Microbial Contamination
• Condensation from Gas Phase
• Process Upsets

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Topsides Pipelines

• Topsides RBI and subsea risk assessments share
  many areas of commonality, in particular
• Internal corrosion risks
• Topside Processing can be the SOLUTION to
  corrosion issues in your pipeline
• For Example
• Improved Separation Processes
• Inhibitor Efficiency
• Dew Point Control
• Improve Process Reliability

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Topsides Pipelines

• Knowledge 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

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Topsides and Pipelines - Example
Offshore Processing
Onshore Processing
Gas Pipeline
Oil Pipeline
Corrosion Coupon
Water Processing
Reservoir
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Topsides and Pipelines - Example
Corrosion Coupon

• Possible Causes
• Poor separation allowing for water carryover
• Inhibitor partitioning time
• Process Upsets
• MIC

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Topsides and Pipelines - Example
The corrosion coupons have not been showing any
evidence of corrosion growth. WHY?
Gas Pipeline
Oil Pipeline
Position in the pipe
Location?
Corrosion Coupon
Water Processing
Reservoir
RBI will identify HIGH risk areas. Interaction
between topside and subsea assurance teams to
determine location that best represents
conditions in the pipeline.
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RBI Operators Integrity Management Strategy
Activities
Integrity Schemes
Corrosion Control Strategy
Monitoring and Mitigation
CRA, FFP CGA (Pipeline)
RBI (Topsides)
Topside Inspection
Pipeline Inspection
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RBI Concept
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Internal Threats

• Internal Corrosion
• Sweet Corrosion
• Sour Corrosion / Cracking Mechanisms
• MIC (Microbiologically Induced Corrosion)
• Oxygen Corrosion
• Other potential mechanisms?
• E.g. Acetic Acid weld degradation

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Ref MACAW Defect Atlas, Dr. Colin Argent
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External Threats

• External Corrosion
• Atmospheric Corrosion
• CUI (Corrosion Under Insulation)
• Chloride pitting of stainless steels
• Galvanic corrosion
• Other potential mechanisms?

Ref HSE Offshore External Corrosion Guide
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Mitigation

• Internal
• Linings
• Inhibitors
• Biocides
• H2S Scavengers
• O2 Scavengers
• Gas dehydration glycol towers and mol sieves
• Dew Point Control
• Material type
• External
• Coatings
• Material type
• Effective maintenance strategy (paint coatings
  and insulation cladding)

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Consequences of Failure
Manning Levels
Fluid Type
Toxicity
Temperature and Pressure
Toxicity
Flammability
Environment
Safety
Location
Failure Mode
Size of Release
Flammability
Fluid Type
Temperature
Production
Commercial Criticality
Loss of Production
Back up systems?
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RBI Concept
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Inspection History
IP 12 13 Model Code of Safe Practice
API RP 570 510
Quantitative
Qualitative
Calculate time to failure based on wall thickness
measurements. Maximum inspection interval ½
remaining service life
Effectiveness and results of inspections are
graded. IP guidelines set out recommended maximum
intervals based on inspection grade
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Outcome of an RBI?
Types of damage expected
Appropriate Inspection Technique
Inspection Frequency
Hotspot locations
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RBI Schemes

• In 2002 HSE funded a study to compare several RBI
  schemes
• Quantitative vs Qualitative
• Black box approach
• Varying levels of detail
• HSE study identified the need for
• A TRANSPARENT process
• A balance between quantitative and qualitative
  methods
• A balance between theory, inspection and
  engineering judgement

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Ref Risk Based Inspection A Case Study
Evaluation of Onshore Process Plant, W Geary,
2002.
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Talisman Assets

• North Sea Operator
• 11 Platforms
• 1 FPSO
• 2 Onshore Terminals
• Network of over 3000 km of subsea pipelines
• Ageing assets, near or past design life
• Previous owners and inspection companies
• Incomplete data set
• Historical data often stored in hard copy only
• Some existing RBI schemes but varied in type and
  complexity
• A unified approach was required

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Talisman RBI Scheme

• Initial Approach
• Talisman had adopted an RBI program
• Based on API half-remaining life approach
• MACAWs initial role to populate and run this
  program
• Problem
• Information was limited or just not available
• Program required complete data set to operate
  successfully
• A common feature of quantitative models
• Gaps in inspection history and lack of confidence
  in results meant that API approach was not
  appropriate

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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 method
• Top down approach, prioritised safety critical
  systems

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Talisman Assets

• Scale of the project
• 11 platforms, 1 FPSO and 2 onshore terminals
• Typical 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 RBIs
• 1700 Stream RBIs
• The project was split into three phases
• Phase 1 - Safety Critical Systems
• Phases 2 3 Less Critical Systems

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RBI The Key Steps
Effective Communications

• MACAW Team
• Stakeholders
• Define Systems and Streams
• Data Collection
• Assess Corrosion Threats and Consequences
• Assess Inspection History
• Review Process
• Documentation and Handover
• Training and Technical Support
• Implementing RBI
• Updating RBIs
• Reviewing RBIs

Define Scope
Transparent Decisions
Audit Handover
Implementation
Live System
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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

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Stakeholders

• Talisman
• Assurance Engineer
• Focal Point Engineer
• Process Engineer
• Chemist
• Offshore Inspection Engineer
• Inspection Company
• Inspection Engineer
• Corrosion Engineer

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Systems and Streams

• Systems are defined by their fluid and function,
  e.g.
• Produced Oil Oil Export
• Gas Compression and Export
• Fuel Gas
• Systems determine equipment to be assessed, such
  as
• Separation vessels
• Heat exchangers
• Streams
• Streams are used to define sections of pipework
  operating under similar parameters, such as
• Pressure
• Temperature
• Material
• Fluid composition
• Added chemicals (e.g. Corrosion Inhibitor
  injection)

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Systems and Streams

• Process Flow Diagram extract
• Before stream mark up

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Systems and Streams

• Process Flow Diagram extract
• After stream mark up

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Data Collection

• Fluid data
• Design and operating details
• Inspection history

Water Cut
Sand Content
CO2
H2S
Bug Count and Type
pH
O2
Corrosion Allowance
Design and Operating Temperature
Material
Design and Operating Pressure
Wall Thickness
Internal Lining
Inspection Type
Results and Conclusions
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Assess Corrosion Threats and Consequences
Internal Corrosion Mechanisms
Likelihood of Failure
Susceptibility
Mitigation
External Corrosion Mechanisms
Likelihood of Failure
Susceptibility
Mitigation
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Assess Inspection History

• Inspection history and grading
• IP 12 and 13 Inspection Grading method
• Modified to incorporate risk
• Example Pressure vessel inspections next slide

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Assess Inspection History
IP recommended maximum interval
Equipment Grade 0 Grade 1 Grade 2 Grade 3
Process Pressure vessels and heat exchangers 36 48 84 144
RBI recommended maximum interval
Internal Inspection Intervals for Vessels and Heat Exchangers (Months) Internal Inspection Intervals for Vessels and Heat Exchangers (Months) Internal Inspection Intervals for Vessels and Heat Exchangers (Months) Internal Inspection Intervals for Vessels and Heat Exchangers (Months) Internal Inspection Intervals for Vessels and Heat Exchangers (Months) Internal Inspection Intervals for Vessels and Heat Exchangers (Months)
Internal Risk   Grade 0 Grade 1 Grade 2 Grade 3
Internal Risk High 24 36 72 84
Internal Risk Medium 36 48 84 144
Internal Risk Low 48 72 144 144
NB Hydrocarbon Systems will always fall into
High and Medium Risk Categories due to the
consequence of failure associated with these
systems
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Review Process

• Staged 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
• Assurance
• Inspection
• Process Engineering
• Production Chemist
• Operations
• Site personnel
• Safety and Environment

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Documentation and Handover

• Documentation of
• Assumptions
• Issues
• Key decisions
• Marked up PFDs and PIDs
• PFDs hyperlinked to RBIs
• References for Data Sources
• RBIs in spreadsheet format
• Change logging
• Live summary sheet

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Linked PFD and RBI Front Sheet
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Risk Assessment and Data Sources
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Change Log and Prompts
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Live Summary Sheet
A
B
C
D
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Training and Technical Support

• Helpdesk set up for ongoing technical support

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Operating the Scheme

• Once handed over the RBI becomes the
  responsibility of the client
• Quality Controls
• Allocated users
• Permissions should be set up so that only persons
  who have attended training sessions may edit the
  RBIs
• Procedures for Updating and Reviewing Internally
• Procedures for sharing RBI information with other
  interested parties
• Subsea Integrity
• Contractors

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Conclusions

• Involve 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

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Thank you for your time,any questions?
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