module 01- introduction offshore

7/27/2019 Module 01- Introduction Offshore

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Introduction to OffshoreRBI

RBI Offshore Training Course

Module 1



INTRODUCTIONS

(Name,

Organisation

type of work,why interested in RBI,

level of English )



Agenda

Time Day 1 Day 2

09:00 Introduction Module 4

Materials, Degradation

& probability of failure09:15 Module 01

RBI Concept

10:00 Break

10:15 Module 02

Topsides Process11:00 Case Study:

Probability of failure

screening 11:30

12:00 Lunch Lunch

12:3013:00 Module 03

Intro to Working process

Module 5

Consequence of failure14:00

14:15 Break

14:30 Module 6

Inspection methods &

Planning15:00 Case Study:

Consequence of failure

screening

16:00 Module 7

Risk assessment

17:00 End of day End of day



Aims of the course

• Understand where RBI Offshore sits in your

business

• Understand RBI methods & technology foroffshore

• Interpret RBI findings for inspection planning

• Execute RBI projects



Course content

The course will cover:

• RBI Concept• Offshore process and equipment

• Working procedures and Software

• Materials, degradation and PoF calculation• Consequence assessment

• Inspection methods and planning

• Risk evaluation

• Case study and examination



Module 1:RBI Concept

The module will cover:

– What is RBI ?– Scope of DNV’s RBI

– RBI as part of integrity management

– Basic RBI definitions– What can RBI do for you?

– RBI working process

– Basic statistics for RBI– Relevant RBI documentation



Module 2: Offshore Process & Equipment


• Process, utilities, marine & safety systems andtheir inter-relationships

• The documentation that describes the function

and control of these systems• A description of each system & function

separately, with its major equipment.

• The layout of a typical offshore installation



Module 3:Working procedures & Software


• The working process as developedby DNV

• An outline of the software tool

Synergi RBI Offshore



Module 6:Inspection methods and planning


• Usual inspection techniques found offshore• Limitations of the methods

• Personnel qualifications

• Inspection planning



Module 7: Risk analysis and evaluation


• Calculation of failure risk • Evaluation of the results

• Sensitivity studies

• Incorporation of inspection results

• Simple reporting



Module 4: Materials degradation & PoF


• Materials used in topsides process systems

• Degradation theory - corrosion, erosion, fatigue

• Description of how these are modelled inSynergi RBI Offshore



Module 5: Consequence assessment


• Definition of risk • Risk acceptance criteria

• The risk matrix

• Ignited consequence

• Unignited consequence



Scope of DNV RBI, especially Offshore

Interfield P/LTrunk Pipeline

Onshore

Gas Terminal

Interfield P/L

ComplexTopsides

SatelliteTopsides

Subsea

Subsea

Pipelines

Downstream

•Refineries

•Petrochemicals

•Chemicals

Topsides

Structures



Scope of DNV RBI Offshore

• DNV RBI is concerned with the pressure

integrity of the following:– Process piping offshore

– Pressure vessels offshore

• DNV have a methodology for RBI for pipelines,hulls and structures, and this is under separate

application



Joint Industry Project (JIP)

Objectives/Deliverables:

Development of “Base Resource Document” for upstream RBI DNV Recommended Practice

Sponsored by major oil companies =>

BP/Amoco

Norsk Hydro

PPCoN

Saga

Statoil

Acknowledged by NPD (Norwegian PetroleumDirectorate-Norway regulator)



63

Some Older Offshore RBI Projects – before 2000

Client Installation / plant StartedSaga Petroleum Snorre 1995Statoil 1995ELF, Norway Frigg 1996

Statoil Statfjord A, Quantitative RBI of selected topside systems (pilot study.). 1996CONOCO, UK 1996-1998Schlumberger Yme 1997Statoil Norne 1997Statoil Sleipner A, T & R 1997ADMA-OPCO, UAE 1998Amoco/BP, Phillips, Norsk Hydro,Saga, Statoil, DNV Joint Industry Project (JIP) for development of RBI methodology and best practise. 1998Esso Jotun A FPSO, Jotun B WHD & Balder 1998Hydro 1998Kværner/ ADNOC, UAE Khuff 1998Phillips Petroleum 1998

Saga Petroleum Varg FPSO, Quantitative RBI analysis of piping. Varg Wellhead Platform; Qualitative RBI analysis of piping. 1998Statoil Statfjord 1998Hess / Dong Syd Arne, Quantitative RBI analysis of process piping and vessels 1998-1999Conoco, SNS Viking B & LOGGS 1999

Statoil sgard FPSO 1999Statoil Kårstø gas terminal 1999Statoil Sleipner A/B/T, Quantitative RBI analysis of piping. 1999Statoil Norne FPSO, Quantitative RBI analysis of piping. 1999



Screening matrix

A Detailed RBI

B Insignificant PoF

C

I n s i g n

i f i c a n t C o F

D

PoF

1

10-2

10-3

10-4

10-5

Low ― Consequence― High



The likelihood of failure

will increase over time

because of time-

dependent material

degradation.

Periodic review

Systems screened out

may undergo a changein their process

conditions, and so

develop significant risk

of failure.Consequently there

should be a regular

review of these

screened-out items.A B C D E

Consequence of Failure

L

i k e l i h o o d

o f F a i l u r e



Detailed RBI: Probability of Failure (PoF)



Calculation of PoF

Degradation

Mechanism

Damage Failure

Mode

Loads v.

Strength

•Corrosion

•Fatigue

•Erosion

•Pitting

•Cracks

•Wall loss

•Geometry

•Material type

•Stressintensity

•Remaining

wall

Knowledge of Materials Tells Us What Failure Mode to Expect

L i m i t S

t a t e s

•Pinhole leak

•Brittle

fracture

•Burst

•…..



PoF based on “Load” (S) and “Resistance” (R)

StressPoF = overlapping area

Applied stress is

function of

pressure load &remaining wall

thickness

Resistanceis a

function of

wall

thickness& strength

P r

o b a b i l i t y D

e n s i t y

S

R



PoF example from Synergi RBI Offshore



Detailed RBI: Consequences of Failure (CoF)



Scope of Consequences Assessment

• Hole size distribution modelling => depends on

failure mode (i.e. degradation mechanism)

• Assessment of consequences for various hole

sizes

– safety– economic/business impact

– environment



Safety Consequences

• Expressed in “Potential Loss of Life” (PLL)

• Determine PLL contribution per equipment item• Can use results from QRA, Safety Case or can

use in-built Synergi RBI Offshore consequence

model



Economic Consequences

• Damage requires repair (costs +

strategy)

– Equipment damage

– Module damage after escalation

– Installation damage after escalation

• Production loss

– due to equipment damage

– due to module damage after escalation– due to installation damage after escalation

Forvarious

hole sizes



Environmental Consequences

• Can include clean-up costs, fines, pollution tax,

damage to company reputation, loss of share

value• Environmental Impact Assessments usually

look at large releases. These are mostly greater

than would be lost from any one topside processsegment, but are relevant to pipeline leaks,

blow-outs etc



1

4

2

3

discharge dispersion

ignition

(flammables)

Four stages of a release

consequence



Well fluid

Process

gas

Process

condensate

Produced

water

Escalation to

adjacent

areas

CoF: Ignited



CoF Ignited

• Ignited consequence will involve calculation of:

– Loss of life due to fire and explosion– Economic loss due to equipment damage and lost

production

– Environmental damage to the surface may not be

large, as the pollutant burns up. Damage to the air

may be more important.



CoF Unignited

• Unignited consequence will involve calculation

of:

– Economic consequence due to loss of production.This depends on repairing strategy and production

profile during repair

– Loss of material assets from pipes are negligible, will

be different for vessels if they have to be replaced

– Note that environmental damage may be significant

• Safety consequence is rarely significant for non-

hydrocarbon systems, but may be so when

considering high pressures



Risk evaluation

• PoF is calculated where the “load” probability

exceeds the “Resistance” probability - i.e., the

overlapping area of the two probability densityfunctions.

• Synergi RBI Offshore will calculate PoF, CoF,

risk, time to risk limit, and advise of degradation mechanism.

• We look at what is influencing the risks, and

advise on how they are best monitored andcontrolled.



Deliverables from a DNV RBI Study

• Equipment items ranked in order of risk

• “Inspection plan” per equipment item:

How to inspect or monitor (inspection technique, critical parameter)

Where to inspect (location, coverage)

How often to inspect (time to next inspection)

• Quantitative model, enables: Sensitivity analysis on:

Change of operating conditions, fluid composition

Change of material, coating etc.

Inspection frequency

Inspection effectiveness of tool

Cost/Benefit analysis



Basic statistics for RBI

• There are a few simple statistical concepts that

are needed for RBI, covering the description of

distributions of data

• The PoF models consider distributions of

probability of an event, so there is no one fixed

value as in deterministic modelling

• The distributions are described using the

following parameters:

– Mean

– Standard Deviation (SD)

– Coefficient of Variation (CoV)



Distributions used in Synergi RBI Offshore

• The distribution will reflect the process

generating the data, so when fitting distribution

to data, be sure that the data is from only onestatistical population.

• Relevant distributions are:

– Normal:• Most common form of probability density function of a

continuous random variable

– Log normal– Exponential

– Weibull

– Gumbel



Normal distributions

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8

Mean

Standard Deviations

0.5

1.0

2.0



Log normal distribution

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0 5 10 15 20 25

Mean

Standard Deviations

0.1

1.0

10



Exponential distribution

0

0.5

1

1.5

2

2.5

0 1 2 3 4 5 6 7 8

Series1Series2

Series3



Weibull distribution

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 0.5 1 1.5 2 2.5 3 3.5

model uncertainty

p r o b a b i l i t y d e n s i t y f u n c t i o n

W(1.0;0.45)

W(0.4;0.8)



Relevant documentation

• DNV are have produced a Recommended

Practice for upstream RBI DNV RP G101, with

appendices

• API Recommended Practices RP 580, RP 581

• ASME - Risk-based inspection guidelines



Safeguarding life, property

and the environment

www.dnv.com

98

module 01- introduction offshore

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