Risk Based Inspection (RBI) - A Transparent Process?

1. 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 1

2. Introduction • Topsides & Pipelines • RBI & Operators Integrity Management Strategy • RBI Concept & Schemes • Talisman RBI Process – MACAW Experience • Conclusions • Questions 2

3. 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 Introduction 3

4. 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” Introduction 4

5. 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 5

6. 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 6

7. 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 7

8. Topsides and Pipelines - Example Offshore Processing Onshore Processing Gas Pipeline Oil Pipeline Corrosion Coupon Water Processing Reservoir 8

9. Topsides and Pipelines - Example Corrosion Coupon • Possible Causes: • Poor separation allowing for water carryover • Inhibitor partitioning time • Process Upsets • MIC 9

10. 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. 10

11. RBI & Operators Integrity Management Strategy Activities Integrity Schemes Corrosion Control Strategy Monitoring and Mitigation CRA, FFP & CGA (Pipeline) RBI (Topsides) Topside Inspection Pipeline Inspection 11

12. RBI Concept 12

13. Internal Corrosion Sweet Corrosion Sour Corrosion / Cracking Mechanisms MIC (Microbiologically Induced Corrosion) Oxygen Corrosion Other potential mechanisms? E.g. Acetic Acid weld degradation Internal Threats 13 Ref: MACAW Defect Atlas, Dr. Colin Argent

14. External Corrosion Atmospheric Corrosion CUI (Corrosion Under Insulation) Chloride pitting of stainless steels Galvanic corrosion Other potential mechanisms? External Threats Ref: HSE Offshore External Corrosion Guide 14

15. 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) 15

16. 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? 16

17. RBI Concept 17

18. 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 18

19. Outcome of an RBI? Types of damage expected Appropriate Inspection Technique Inspection Frequency Hotspot locations 19

20. 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 20 Ref: Risk Based Inspection – A Case Study Evaluation of Onshore Process Plant, W Geary, 2002.

21. 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 21

22. Talisman RBI Scheme • Initial Approach • Talisman had adopted an RBI program • Based on API half-remaining life approach • MACAW’s 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 22

23. 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 23

24. 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 Talisman’s 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 24

25. Effective Communications RBI – The Key Steps • 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 RBI’s • Reviewing RBI’s Define Scope Transparent Decisions Audit & Handover Implementation Live System 25

26. 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 26

27. Stakeholders • Talisman • Assurance Engineer • Focal Point Engineer • Process Engineer • Chemist • Offshore Inspection Engineer • Inspection Company • Inspection Engineer • Corrosion Engineer 27

28. 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) 28

29. Process Flow Diagram extract Before stream mark up I J K E G F B H C D A Systems and Streams 29

30. Process Flow Diagram extract After stream mark up Systems and Streams 12 30

31. 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 31

32. Assess Corrosion Threats and Consequences Internal Corrosion Mechanisms Likelihood of Failure Susceptibility Mitigation External Corrosion Mechanisms Likelihood of Failure Susceptibility Mitigation 32

33. Assess Inspection History • Inspection history and grading • IP 12 and 13 Inspection Grading method • Modified to incorporate risk • Example Pressure vessel inspections – next slide 33

34. Assess Inspection History IP recommended maximum interval RBI recommended maximum interval NB: Hydrocarbon Systems will always fall into High and Medium Risk Categories due to the consequence of failure associated with these systems 34

35. 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 35

36. Documentation and Handover • Documentation of • Assumptions • Issues • Key decisions • Marked up PFD’s and P&ID’s • PFD’s hyperlinked to RBI’s • References for Data Sources • RBI’s in spreadsheet format • Change logging • Live summary sheet 36

37. Linked PFD and RBI Front Sheet 37

38. Risk Assessment and Data Sources

39. Change Log and Prompts 39

40. Live Summary Sheet A B C D 40

41. Training and Technical Support • Helpdesk set up for ongoing technical support 41

42. 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 RBI’s • Procedures for Updating and Reviewing Internally • Procedures for sharing RBI information with other interested parties • Subsea Integrity • Contractors 42

43. 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 43

44. Thank you for your time,any questions? 44