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Otto Huisman
Arash Gharibi
Sebastian Ruik Beyhaut
ROSEN Integrity Solutions
GEOHAZARD IDENTIFICATION AND ASSESSMENT FOR GAS PIPELINES
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Slide 2
• Engineering & Consultancy Company within the ROSEN Group
• Data Management, Integrity & Consulting, Software Services
• Human Power:
• 35 Employees involved in Data & GIS Management
• 50 Software Developers
• 80 Integrity Engineers
ROSEN GROUP: INTEGRITY SOLUTIONS
Technical Support /
Data Services
Software Development
Team
Integrity Engineering
Team
Software Product
Development and
Customization
Post-ILI and
Engineering
Consultancy
PIMS Implementation
Projects and Product
Definition
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 3
The key objective of this presentation is to illustrate a GIS-based methodology for determining the location and expected significance of
geo-hazards along a pipeline, drawing on examples for a gas pipeline in New Zealand.
Specifically, the presentation will:
• Introduce Geohazards as complex processes
• Discuss risk, threats and consequence
• Illustrate examples of:
1. Determining soil instability
2. Determining aggregate geohazard threats to the pipeline
• Provide some conclusions
OBJECTIVE
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 4
• Landslides/mass movement
• Tectonics/seismicity
• Hydrotechnics
• Erosion and upheaval displacement
• Geochemical
• Freezing of unfrozen ground
• Thawing of permafrost terrain
• Unique soil structure
• Desert mechanisms
• Volcanic mechanisms
Source: M. Rizkalla (ed.), 2008. “Pipeline Geo-Environmental Design and Geohazard Management”
GEOHAZARDS INCLUDE…
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 5
• Characterised by very high spatial variability
• Often dynamic
• Not as predictable as we would like
• Complex
• etc.
Key question remains: “What (and where) are the risks to my pipeline?”
An ideal ‘answer’ to this question would
consider expert local knowledge (e.g. from
operator staff).
GEOHAZARDS ARE…
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 6AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
GAS PIPELINES: CONSEQUENCES
• Model specified by
MACAW• Implemented in GIS
• Results feed the
consequence parameters of
QPRAM risk model in ROAIMS
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Slide 7
ASSESSMENT OF RISKS TO THE PIPELINE
A client-specific risk model should answer the following basic questions:
• Which threats are active?
• Will the active threat result in a leak or a rupture?
• What is the company liability in the event of a failure?
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 8
• Central-western part of North Island
• Approx. 390km of gas pipeline (main
backbone only).
• Extremely varied terrain: unique
challenges for field monitoring teams
CASE STUDY: MAJOR GAS OPERATOR IN NEW ZEALAND
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 9
Two analyses follow:
1) A methodology for identifying and prioritizing locations of ground
instability along the pipeline for foot patrol and possible remediation
2) A methodology for determining ‘aggregate’ geohazard threats to the
pipeline
For each of these analyses we will need to pay significant attention to:
- Data sources
- Identification of hazards
- Analysis and combination
- Visualisation
CASE STUDY: NEW ZEALAND GAS PIPELINE
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 10
1. GROUND INSTABILITY
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 11
Semi-automated methodology which makes use of a range of spatial data:
• High resolution imagery
• Digital Elevation Models
• Soil and land cover databases
• Rainfall and rivers data
• Earthquakes and fault lines data
• Supplementary data from client where appropriate and/or available
INPUT DATA
Data Mining (C4.5)
Weight Class Category Weight
0.136 Slope >45 0.154
35-45 0.311
20-35 0.423
10-20 0.063
10> 0.049
0.13 Bending Strain Yes 0.833
No 0.167
0.122 Water Resource Yes 0.833
No 0.167
0.192 Ground Instability (Landslide) Yes 0.833
No 0.167
0.077 Precipitation (Rainfall) >3000 0.489
2000-
3000 0.232
1000-
2000 0.19
>1000 0.089
0.147 Seismic Intencity >7 0.727
5-7 0.2
5> 0.073
0.054 Freezing/Thawing Yes
No
0.082 Erosion High 0.717
Medium 0.217
Low 0.066
0.06 Seismic Frequency ???
ANP + weighted overlay (ArcGIS toolbox)
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 12
Combined instability zones:
• Data mining of New Zealand Land
Resource Inventory (LRI)
• Spatial model using soil type, rainfall and Digital Elevation Model (DEM)
• Total extent of occurrence (max area)
GROUND INSTABILITY AREAS
Erosion form name
Debris avalanche
Earthflow
Earth slip
Mudflow
Soil slip
Rockfall
Slump
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 13
COMBINING GEOHAZARDS
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 14
• Reclassification and combination of available data
from multiple data sources
• Use of modelling tools to derive weightings from best practice documents and published sources on
geotechnical risk.
• Additional threat drivers/geohazards can be added
as necessary.
INPUT DATA
Class
Slope
Ground Instability
Precipitation
(Rainfall)
Seismic Intensity
Freezing/Thawing
Erosion
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 15
MODEL GEOHAZARDS TO IDENTIFY ‘AGGREGATE’ VALUE: INPUT DATA
Slope is made up of thenational New Zealand DEMfile with a resolution of 11meters
Ground instability is (partially)derived from analysis onnational Land ResourceInformation (LRI),
Rainfall dataset is made upof the average rain fall of thelast 25 years of NewZealand.
Seismic intensity is made up ofEarthquake dataset of last 30 years.
Impact zone of the earthquakes iscalculated based on the studies onregistered hazard zones.
Freezing and Thawing iscalculated based on clusteredaverage temperature of all thedays of the last 30 years.
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Slide 16
• Each hazard is assigned a weight
• Each category within the hazard is
also assigned a weight
• These can be derived from data
mining existing failure reports or
databases
• Aim is to get domain expert input
into weighting to assess the relative importance of each hazard within a
give zone or area.
ESTABLISHING WEIGHTS FOR COMBINING GEOHAZARD THREATS
Weight Class Category Weight
0.175 Slope >45 0.154
35-45 0.311
20-35 0.423
10-20 0.063
10> 0.049
0.139 Proximity to water Yes 0.833
No 0.167
0.203 Ground Instability Yes 0.833
No 0.167
0.098 Precipitation >3000 0.489
2000-3000 0.232
1000-2000 0.19
>1000 0.089
0.195 Seismic Intensity >7 0.727
5-7 0.2
5> 0.073
0.075 Freezing/Thawing Yes 0.901
No 0.099
0.115 Erosion High 0.717
Medium 0.217
Low 0.066
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 17
Use of Analytic Network Processing methodology (ANP) to deal with complexity: categories within each
class are treated separately
Each class is assigned a rank, and a
decision matrix is generated, where
the resulting weights are based upon the principal eigenvector
Mapping and classification can be used for visualizing results...
ESTABLISHING WEIGHTS FOR COMBINING GEOHAZARD THREATS
Weight Class Category Weight
0.175 Slope >45 0.154
35-45 0.311
20-35 0.423
10-20 0.063
10> 0.049
0.139 Proximity to water Yes 0.833
No 0.167
0.203 Ground Instability Yes 0.833
No 0.167
0.098 Precipitation >3000 0.489
2000-3000 0.232
1000-2000 0.19
>1000 0.089
0.195 Seismic Intensity >7 0.727
5-7 0.2
5> 0.073
0.075 Freezing/Thawing Yes 0.901
No 0.099
0.115 Erosion High 0.717
Medium 0.217
Low 0.066
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 18
AGGREGATE GEOTECHNICAL HAZARD
Areas of
concern/ prioirity
for combinedgeohazards
Resolution: ~400m grid cell
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 19
96% of bending strain
segments found to lie within either ‘red’ or
‘orange’ geohazard
zones
EVALUATION OF RESULTS: OVERLAY WITH BENDING STRAIN
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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Slide 20
• Geohazards represent complex threats to a pipeline
system
• ‘Good’ data required for their accurate assessment, but a good methodology is also essential
• New approaches in handling complex processes can be deployed ‘in a spatial context’
• GIS modelling approaches can provide useful inputs into risk assessment process, but also as ‘screening’ for more
detailed assessment and mitigations.
CONCLUSION
AGA 2015 Conference · Huisman, Gharibi and Ruik Beyhaut · © ROSEN Group · 30-April-2015
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