Risk Based Inspection

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. 3
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

4. 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”
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
Reservoir
Gas Pipeline
Oil Pipeline
Offshore Processing Onshore Processing
Corrosion
Coupon
Water
Processing
8

9. Topsides and Pipelines - Example
Corrosion
Coupon
Possible Causes:
• Poor separation allowing for water carryover
• Inhibitor partitioning time
• Process Upsets
• MIC
0
45
90
135
180
225
270
315
360
0 10 20 30 40 50 60
Distance - Km
Orientation
-
degrees
9

10. Topsides and Pipelines - Example
Reservoir
Gas Pipeline
Oil Pipeline
Corrosion
Coupon
RBI 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
pipe
Location?
Water
Processing
10

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

12. RBI Concept
12
IDENTIFY THREATS/
HAZARDS
to EQUIPMENT
(Pipework, Vessels etc)
SUSCEPTIBILITY to
THREAT
MITIGATION
MEASURES to
REDUCE
SUSCEPTIBILITY
LIKELIHOOD of
FAILURE
FAILURE MODE
CONSEQUENCES of
FAILURE
ASSESS
INSPECTION
HISTORY
REMAINING LIFE or
INSPECTION GRADE
IDENTIFY THREATS/
HAZARDS
to EQUIPMENT
(Pipework, Vessels etc)
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
SCHEME

13. 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
Ref: MACAW Defect Atlas, Dr. Colin Argent 13

14. 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
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
Consequence
of Failure
Safety Environment
Production
Fluid Type
Failure
Mode
Manning
Levels
Temperature
and Pressure
Flammability
Toxicity
Size of
Release
Fluid Type
Location
Temperature
Flammability
Toxicity
Commercial
Criticality
Back up
systems?
Loss of
Production
16

17. RBI Concept
17
IDENTIFY THREATS/
HAZARDS
to EQUIPMENT
(Pipework, Vessels etc)
SUSCEPTIBILITY to
THREAT
MITIGATION
MEASURES to
REDUCE
SUSCEPTIBILITY
LIKELIHOOD of
FAILURE
FAILURE MODE
CONSEQUENCES of
FAILURE
ASSESS
INSPECTION
HISTORY
REMAINING LIFE or
INSPECTION GRADE
IDENTIFY THREATS/
HAZARDS
to EQUIPMENT
(Pipework, Vessels etc)
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
SCHEME

18. Inspection History
Inspection
History
Remaining
Life
Inspection
Grading
API RP
570 & 510
IP 12 &13
Model Code of
Safe Practice
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
Quantitativ
e
Qualitative
18

19. Outcome of an RBI?
What? How?
When?
Result of an RBI
Where?
Types of
damage
expected
Inspection
Frequency
Appropriat
e
Inspection
Technique
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
Ref: Risk Based Inspection – A Case Study Evaluation of Onshore Process Plant, W Geary, 2002. 20

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. 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
Effective
Communications
Implementation
Live System
25
Define Scope
Transparent
Decisions
Audit & Handover

26. Project Manager (1)
Senior Corrosion Engineers (2)
Project Supervisors (3)
Technical Assistants (6)
MACAW Team
26
• Team is set up to work on 6
RBI projects at a time
• Data intensive process
• Engineering assessment
required on missing data

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

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

31. Data Collection
– Fluid data
– Design and operating details
– Inspection history
CO2 H2S
pH
Water
Cut
Material
Wall
Thickness
Design and
Operating
Temperature Design and
Operating
Pressure
Corrosion
Allowance
Internal
Lining
Bug Count
and Type
O2
Sand
Content
Inspection
Type
Results and
Conclusions
31

32. Assess Corrosion Threats and Consequences
Internal
Corrosion
Mechanisms
Susceptibility Mitigation Likelihood of
Failure
External
Corrosion
Mechanisms
Susceptibility Mitigation Likelihood of
Failure
High Medium High High
Medium Low Medium High
Low Low Low Medium
Low Medium High
Internal
Likelihood
of
Failure
INTERNAL RISK
Consequence of Failure
High Medium High High
Medium Low Medium High
Low Low Low Medium
Low Medium High
Consequence of Failure
External
Likelihood
of
Failure
EXTERNAL RISK
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
Equipment Grade 0 Grade 1 Grade 2 Grade 3
Process Pressure vessels and
heat exchangers
36 48 84 144
Internal Inspection Intervals for Vessels and Heat Exchangers (Months)
Internal
Risk
Grade 0 Grade 1 Grade 2 Grade 3
High 24 36 72 84
Medium 36 48 84 144
Low 48 72 144 144
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. A
C
D
B
Live Summary Sheet
40

41. Training and Technical Support
• Helpdesk set up for ongoing technical support
41
Date:
Request
from:
Contact details: Asset: RBI File name:
Q.A.P 4.26.1
08/10/2007
Request
MACAW RBI Help Request form

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