rug 2013 - new tools for offshore qra

New tool for Offshore QRAPhast & Safeti User Conference 2013

Det Norske Veritas AS. All rights reserved.

New tool for Offshore QRA

Background

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Over the years, DNV has developed a number of tools for safety analysis of Offshore installations

Offshore Hazard and Risk Analysis Toolkit (OHRAT)- First version released in 1992 in direct response to Piper Alpha disaster- Joint industry project with numerous Operators, Consultants and EPCs

Neptune- The OHRAT concept taken into Microsoft Windows environment (1999)

Spreadsheet models (e.g. SOQRATES) (2005+) Phast also used for Offshore consequences

All these tools have their own respective benefits and drawbacks

As a result, in 2009 DNV started discussing a new tool to harness our Offshore experience so far and build a new tool for the future

Welcome to Safeti Offshore - everything DNV knows about Offshore QRA encapsulated within one, comprehensive tool



Safeti Offshore A joint collaboration involving significant investment between:

- DNV Advisory Services, providing their Offshore QRA and domain experience- DNV Software, delivering software engineering and mathematical modelling expertise

Design discussions during 2009-2010

Project and coding kick-off January 2011, starting with Proof of Concept First internal release delivered Q1 2013, plus regular ongoing releases Key project goals:

- Develop an integrated and uniform approach to Offshore QRA based upon international standards such as ISO 17776 and NORSOK Z013

- Integration of separate QRA models within one common software tool- Support risk management throughout the lifecycle of an installation from planning to

decommissioning- Provision of a standardised tool building on the well-established Phast architecture

- Benefit from software economies of scale- Develop a new, commercially successful software product

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Merging of Tools and Competence

SafetiOffshore

Leak

NEPTUNE / SOQRATES

Other Standalone

Tools

EXPRESS

Phast / Phast Risk

New ModelsEXPRESSMODFIRE



New Developments and Features

Integrated smoke

modelling

Time varying discharge, with safety systems

Subsea releases

Choice of ignition models 3D viewer

Confined module fire

model

Detailed impairment estimation

Detailed escalation modelling

Escape and Evacuation modelling

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Whats new in Safeti Offshore? Safeti Offshore incorporates some significant new technology

Offshore asset hierarchy

Automatic release case generation (subject to user defined rules) 3-D graphical input and results viewer

Graphical Event Tree viewer

Powerful data input grid

New mathematical modelling, including:- Improved discharge modelling, allowing for safety systems:

- Detection, isolation and blowdown- Integration of DNV Express, a probabilistic model for module explosions- New compartment fire model taking into account module geometry and flame development- Subsea releases- Escalation modelling

Plus everything else that Safeti contains

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Leak

LocationIS1-G

1.000E-14

1.000E-13

1.000E-12

1.000E-11

1.000E-10

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1.000E-02

1.000E-01

1.000E+00

0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0 1600.0 1800.0 2000.0

P

r

o

b

a

b

i

l

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t

y

Time [s]

Cumulative Probability of Ignition

Small (main)

Medium (main)

Large (main)

Leak

LocationIS1-G\Explosion Target

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1.000E-02

1.000E-01

1.000E+00

0.0000 0.2000 0.4000 0.6000 0.8000 1.0000 1.2000

P

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a

b

i

l

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y

(

g

i

v

e

n

I

g

n

i

t

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o

n

)

Pressure [bar]

Aggregated Exceedance Probability vs Explosion Overpressure

Small (main)

Medium (main)

Large (main)

New probabilistic explosion model - EXPRESS EXPRESS is used to calculate the following:

- Flammable cloud dispersion in source module (cloud volume)- Detection, Ignition and Explosion probabilities- Explosion Overpressure Exceedance Curves (at each defined target)

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MODFIRE: 3D Fire Modelling Bridges the gap between existing Phast

fire models and CFD

Builds upon the existing Phast fire models by combining them in new ways

Fires begin in the source module

Fires allowed to develop and escalate beyond the source module:- Overall volume of the flame is conserved

and spread over the platform in accordance with layout and geometry

Also handles scenario where fire walls are damaged or removed by initial explosion prior to fire

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Safeti Offshore Basic Input Workflow Assets tab:

Define Installation Areas Define Safety Barriers, Walls and Decks Define Escape Routes Define Structural Elements

Process Tab: Define Isolatable Sections Define Equipment items Define Process Case options Define Risers & Pipelines Define Wellgroups

Generate Leak Locations (Scenarios) and Cases (Safety Systems) for each section

Add User Defined Scenarios

Assign Explosion Targets & Vulnerabilities

Define other data: Materials

Weathers

Worker population

Then perform the calculations: Inventory volume Leak frequencies Consequences (Explosion & Fire) Risk

Review results and perform sensitivity analysis

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Safeti Offshore at a glance

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RIBBON BAR

GRIDASSETHIERARCHY

TABS

3D VIEWER



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Lets unpack this a bit more...



Ribbon Bar The Ribbon bar

Key interface area in terms of running calculations and viewing results- Includes grid search facility

Allows for staged, sequential model runs- Case definition (Volume, frequency,

screening), Consequence (TVDI, EXPRESS) and Risk

Event trees can be visualized and drilled down into

Results (risk and consequence) can be viewed from the 3D viewer

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Running Steps

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Data Input(Asset, Process, Weather,

Risk, Material, Parameters)Volume & Frequency

(Process Tab)

Generate Process Leak Locations &

Cases (Right Click on Process Tab)

Volume & Frequency & Screening(Model Tab)

Define Express Targets & Additional Input

(Model tab)

DischargeTVDI

(Model Tab)

EXPRESS Explosion (Model Tab)

Consequence Dispersion(Model Tab)

Risk (Model Tab)

More details later



Asset Hierarchy Key element of the tool

This is where the structure/outline of facility is defined

Built in a modular fashion using key objects- Installation- Platform- Areas- Walls- Decks- Structural elements- Escape routes

Key aspect of the tools spatial awareness- Every object has a location- Key characteristics of objects are also defined (notably resilience to impacts) - For example, fire and blast rating for walls and decks (Vulnerability)

Also allows for three release types/locations Topsides, Above sea, Subsea

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Object definition Walls and Decks

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Object definition - Areas

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Object definition Escape Routes

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Graphical Illustration of the above

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Deck(Upper face)

Area(cuboid)

Wall(Outer face)

Wall(Inner face)

Escape Route



Safeti Offshore - Release Locations

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Subsea

Above sea

Inside



3D Viewer(facilities) Safeti Offshore provides comprehensive 3D view of platform and results

Key for QA, communication and visualisation of results

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Sea

Sea Bed



3D Viewer(facilities)

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3D Viewer(Consequence Results)

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Explosion overpressure

radii

Fire size & flame effects Smoke and

toxic effects



3D Viewer(Risk Results) The 3D viewer also allows for risk

results to be viewed for the object selected

Results available include- PLL- Escalation- Impairment- Personnel - Overpressure

Results are output to a results file- Excel or Access

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Tabs Safeti Offshore includes 10 tabs

Titles are largely self-explanatory, details not so much

Provide a structured systematic way to organize the data and thus run a QRA

We shall examine two key tabs

Process tab

Risk Tab

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Process Tab Process tab

- Define Isolatable sections and parts count- Define sizes to consider Small, Medium

or Large- Model as release rate or hole size- Availability of safety systems (Isolation and

Blowdown)- Frequency analysis settings (Full, Limited,

Zero pressure etc.) Automatic case generation of models to

Models tab

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Risk Tab Risk tab

Where all risk data is defined- Populations- Ignition- Vulnerabilities - Run rows etc.

Failure of barriers also considered - Pressure reduction factor on failure- Deluge parameters

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Overview of Typical Results (1) Results related to frequency, consequence and risk results

Frequency results- Generally frequencies per year for the specific end events- Grouped frequencies per year according to high-level hazard categories- Grouped frequencies by area of the platform

Consequence results- Discharge, release rate data (by event scenario and safety system) including flow rate,

duration, time varying- Explosion results: EXPRESS / DAL detailed results; overpressure / impact at targets;

escalation result- Fire results: fire and radiation extent; impact at targets; escalation result - Toxic results: dispersion extent; impact at targets- Smoke results: dispersion extent; impact at targets

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Risk Results Detailed risk results produced for each potential outcome

- IR, IRPA, PLL, Escalation, Impairment, Exceedance Curves (explosion, flammable)- Ignition probabilities (TDIIM) and many more

Work on-going to develop more sophisticated reporting mechanisms

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Ongoing Risk Consultancy projects with Safeti Offshore DNV now gaining invaluable experience applying Safeti offshore to live projects One significant project currently underway

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Looking forwards Immediate future:

- Extensive -Testing program, based on real reference projects- Market planning and communication (e.g. DNV Software User Conferences)

Medium-term:- Further consultancy projects- Parallel deployment of Software and Advisory Services to our existing customers

Longer-term:- Ongoing feature development & improvement

- Enhanced user friendliness- Improved calculation runtimes

- Release of new version(s)- Full commercialisation and rollout to broader customer base

Do you have specific needs for your own Offshore QRA analysis?- Please come and talk to us we can add

- New and alternative calculation models- Specific features and customisations

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Safeguarding life, property and the environment

www.dnv.com

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rug 2013 - new tools for offshore qra

Documents

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