Cumulative Quantitative Risk Assessment of an Onshore Oil ...
Transcript of Cumulative Quantitative Risk Assessment of an Onshore Oil ...
Cumulative Quantitative Risk Assessment of an Onshore Oil and Gas Industrial Site: A Case Study
Srinivas Sambasivam, et. al.HSE&R, W S Atkins,
Houston, USA
Agenda
• Project Description• Key Challenges• Methodology• Field Survey and GIS Map Development• Consequence and Frequency Analysis• Risk Analysis using Atkins “RiskTool”• Conclusions
Project Description
• Primary Objective – Cumulative QRA of an Oil & Gas Industrial Site.
• Site consists of several Oil & Gas Processing Facilities.• Facilities are Operated by Local, National and International
Oil & Gas Operating Companies.• Other Key Objectives
• Identify Key Risk Drivers • Develop Site Wide Emergency Evacuation Plant• Identify Scenarios that can Escalate Between Individual
Facilities.• Provide Input for Future Land Use Planning
Industrial Site – Major Facilities
Industrial Site – Onshore Wells
Oil Wells (45Nos.)
Industrial Site – Buried Pipelines
Onshore Buried Oil and Gas Pipelines(26Nos.)
Cumulative QRA
• Slug Catcher Facilities• Oil Tank Farm• Condensate Station• Pig Launching /Valve Stations• Number of Onshore Oil Wells• Number of Onshore Oil and Gas Buried Transmission
Pipelines• Number of Oil Gathering Lines Located Onsite
Key Challenges
• Local Resource Availability• Limitations in the Availability of Input Data• Non-Availability of Integrated GIS Map for the Entire
Industrial Site.• Risk Modeling Constraints
• 200 Plus Release Scenarios Resulting in Approximately 4,500 Hazardous Events.
• About 90 Pipeline (Linear) Scenarios.• Variations in Population Distributions Throughout the Site.• Large Area (approximately 22 sq. km) of Study.
Methodology
The QRA was Planned and Executed in the Following Stages:• Data Collection and Review.• Field Survey.• GIS Map Development.• Development of Assumptions Log.• Frequency and Consequence Modeling.• Risk Modeling.• Presentation of Results.• Report Preparation.
Resource Management
COLLABORATIONCOLLABORATION• Collaborative Effort• Teams from
• Houston, USA• Port of Spain, Trinidad• Warrington, UKCOLLABORATIONCOLLABORATION
Project Execution Methodology
INTEGRATION
Field Survey and GIS Map DevelopmentTECHNOLOGY DRIVENTECHNOLOGY DRIVEN
• Use of Geographical Information System (GIS)
• Site Data Captured Using
• Satellite Imagery• Site Survey
Conducted Using Mapping Tools
• Desktop Analysis using ArcGIS Package
TECHNOLOGYTECHNOLOGYDRIVENDRIVEN
Field Survey
Field Survey
Field Survey
Desktop Analysis – GIS Map
Frequency and Consequence AnalysisFrequency Analysis• Parts Count was Performed for the Process Systems.• OIR12 Failure Data was Used to Determine the Release Frequency.• Event Trees Generated Using Various Ignition Models.
Consequence Analysis• The study addressed the following events
• Jet Fires• Pool Fires• Explosions• Flash Fires
• DNV’s PHAST and Atkins “RiskTool” used for Consequence Modeling.
Risk Analysis
INNOVATIONINNOVATION
INNOVATIONINNOVATION• Atkins In-house Developed
QRA Software – “RiskTool”• RiskTool Customized To Model
Up To • 4,500 Hazardous Events, • 14 Different Population Areas
and • 100 Pipe Segments
• Population could be defined in number of ways.
• Risk Analysis Could be Done for Different Weather Conditions
• Can Integrate Consequence Modeling
• Can Import GIS Data• Generates
• Individual Risks• Geographical Risk Contours
Using Surfer Integration• F-N Curves
Start
Enter Grid Definition and Project Description Data
Enter Site-Layout Coordinates
Enter Pipeline Coordinates
Enter Population Data
Input Scenario Data
Input Meteorological Data
Save Project Data
Calculate Conditional Risk
Calculate Individual Risk
Summary
Calculate Societal Risks
Calculate Individual Risk
Transect
Calculate Individual Risk
Grid Results
End
View Outputs
RiskTool P
roject Set-U
p Steps
RiskTool – Input Screen
RiskTool – Site Layout Data
RiskTool – Pipeline Route Data
RiskTool – Site Layout
RiskTool – Scenario Screen
RiskTool – Simple Foot Print Model
RiskTool – Weather Categories
RiskTool – Population Definition at Specific Locations
RiskTool – Population Definition Using Population Distribution Grid
Results – Individual Risk Summary
Indi
vidu
al R
isk
Per A
nnum
Distance in meters
Results – Individual Risk Transect
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
-1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 100 200 300 400 500 600 700 800 900 1000
Distance from pipeline (metres)
Ris
k of
rece
ivin
g a
dang
erou
s do
se o
r wor
se (p
er y
ear)
Total risk from all events
1 Rupture fireball and jet fire
2 Rupture jet fire
3 Rupture flash fire (D5)
4 Rupture flash fire (F2)
5 Puncture jet fire
6 Puncture flash fire (D5)
7 Puncture flash fire (F2)
8 Rupture pool fire
9 Puncture pool fire
Indi
vidu
al R
isk
Per A
nnum
Distance from Pipeline in meters
Results – Geographical Risks
Results – Societal Risks
Cumulative Freq
uency Pe
r Ann
um
Number of Fatalities
Conclusions
The QRA Study for the Industrial Site:• Generated the Cumulative Risks for the Entire Site.• Identified Key Risk Drivers to Industrial Site and Offsite
Residential Area.• Identified Potential Scenarios That Can Cause Escalations
Between Different Facilities.• Provide Input for Developing Site Wide Emergency Evacuation
Plan.• Provide Input for Future Land Use Planning.• Provide Recommendations for Risk Reductions to Individual
Operators and Site Management.
Conclusions