RBI 2008-06-Macaw

Risk Based Inspection (RBI) - A Transparent Process?

Presented by: Cheryl Frolish

MACAW Engineering Ltd

Co-Authors: Ian Diggory, Richard Elsdon, Krista McGowanMACAW Engineering Ltd

Richard JonesTalisman Energy (UK) Limited 1

• Introduction

• Topsides & Pipelines

• RBI & Operators Integrity Management Strategy

• RBI Concept & Schemes

• Talisman RBI Process – MACAW Experience

• Conclusions

• Questions

2

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

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

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


• 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


• 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

Topsides and Pipelines - Example

Reservoir

Gas Pipeline

Oil Pipeline

Offshore Processing Onshore Processing

Corrosion Coupon

Water Processing

8


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

Ori

enta

tio

n -

deg

rees

9


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

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

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


to EQUIPMENT






FAILURE MODE


ASSESS INSPECTION

HISTORY


RISK FACTOR

INSPECTION SCHEME

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

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

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

Consequences of Failure

Consequence of Failure

Safety Environment

Production

Fluid Type

Failure Mode

Manning LevelsTemperature

and Pressure

Flammability

Toxicity

Size of Release

Fluid Type

Location

Temperature

Flammability

Toxicity

Commercial Criticality

Back up systems?

Loss of Production

16

RBI Concept

17


to EQUIPMENT






FAILURE MODE


ASSESS INSPECTION

HISTORY



to EQUIPMENT






FAILURE MODE


ASSESS INSPECTION

HISTORY


RISK FACTOR

INSPECTION SCHEME

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

Quantitative

Qualitative

18

Outcome of an RBI?

What? How?

When?

Result of an RBI

Where?

Types of damage expected

Inspection Frequency

Appropriate Inspection Technique

Hotspot locations

19

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

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

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

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

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

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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

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

Stakeholders

• Talisman– Assurance Engineer

– Focal Point Engineer

– Process Engineer

– Chemist

– Offshore Inspection Engineer

• Inspection Company– Inspection Engineer

– Corrosion Engineer

27

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

Systems and Streams

• Process Flow Diagram extract

– Before stream mark up

A

B

C D

E

F

G

H

I

J

K

29

Systems and Streams

• Process Flow Diagram extract

– After stream mark up

12

30

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 TypeO2

Sand Content

Inspection Type

Results and Conclusions

31

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

Inte

rnal

L

ikel

iho

od

o

f F

ailu

re

INTERNAL RISKConsequence of Failure

High Medium High High

Medium Low Medium High

Low Low Low Medium

Low Medium High

Consequence of Failure

Ext

ern

al

Lik

elih

oo

d

of

Fai

lure

EXTERNAL RISK

32

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

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

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

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

Linked PFD and RBI Front Sheet

37

Risk Assessment and Data Sources

Change Log and Prompts

39

A

CD

B

Live Summary Sheet

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Training and Technical Support

• Helpdesk set up for ongoing technical support

41

Date:Request

from:Contact details: Asset: RBI File name:

Q.A.P 4.26.108/10/2007

Request

MACAW RBI Help Request form

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

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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?

44

RBI 2008-06-Macaw

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