eo-based ice and iceberg monitoring in support of offshore ... · 35-40 0.94 0.93 0.76 0.78 0.82...
TRANSCRIPT
EO-Based Ice and Iceberg Monitoring
in Support of Offshore Engineering Design and
Tactical Operations
Desmond Power, C-CORE
ESA Industry Workshop on Satellite EO for the Oil and Gas Sector
Overview
• Operations in ice infested waters
• Ice load analysis– Sea ice– Iceberg
• Ice management– Impact on design loads – Technologies
• Role of EO in Design and Operational Ice Management– Sea ice charts– Iceberg surveillance– Near-real-time services
Oil and Gas Operations in Ice Infested Waters
Ability to operate dependent on a number of factors
• Type of structure• Met Ice Ocean environment• Knowledge of ice conditions
– Icebergs– Sea-ice
• Ability to manage ice conditions
• Knowledge of the ice loading on a particular structure
Sea Ice Design Loads
• Characterization of ice/metocean environment
• Sea Ice Encounter Frequency– floe diameter, thickness, drift velocity,
facility size, concentration
• Ice - Structure Interaction– Structure shape, crushing,
contact area– Ice types, ice clearing mechanisms
• Risk Mitigation– Ice breaking
• Loads– Limit stress – failure of ice (sheet, ridge)– Limit energy – kinetic energy in ice– Limit force – wind/wave driving force
Iceberg Design Loads
• Characterization of ice/metocean environment
• Iceberg Encounter– Iceberg waterline length,
drift velocity, facility size, areal density
• Ice - Structure Interaction– Crushing, spalling, contact area – Ice mechanics, strength
• Risk Mitigation– Modeling detection and towing
• Impact Loads– Global - kinetic energy
(mass, impact velocity), eccentricity, ice pressure, crushing, contact area, penetration
– Local – high-pressure zone, impact duration L
Ut
Structure
Iceberg Management - Benefits
Manage Can’t Manage
OK
Avoid Can’t Avoid
OK HITDisconnect Structure
HIT
Fixed Structure
DetectCan’t Detect
HIT
All Icebergs Potentially Impacting Installation
1 impact / 100 yrs
Influence of Ice Management
1 impact / 10 yrs
Iceberg Design Load
1 impact / 10 yrs
Design load at 10-4 annual probability level*
Iceberg Loads – Influence of Impact Frequency
100
Pro
babi
lity
of E
xcee
denc
e 10-1
10-2
10-3
10-4
* Standard = CAN/CSA-S471-06 and ISO 19906
Iceberg Length Distribution
Waterline length: maximum dimension along waterline – most commonly used metric
Mean – 64.6 mExponential Distribution
L
W
Iceberg waterline length
Pro
babi
lity
of O
bser
vatio
n
Effect of Tactical Avoidance
0
0
1
2
3
4
5
6
7
8x 10
4
Freq
uenc
y
Generic Distributionmean = 44.13
std = 53.1max = 399.95
n = 100000
Length
Freq
uenc
yFr
eque
ncy Population that Hit
Mean length = 6.63m
Generic PopulationMean length = 44m
Larger icebergsthat give
higher loads are avoided
Sea Ice Management
• Icebreaker support– Relieve pressures in confining
pack conditions– Push extreme features away
from rigs – Extend operational season of
floating drill rig
Iceberg Management
SensorIntegration
• Tactical– Ice Detection
• Marine Radar• Satellite SAR• Aircraft and vessel reconn• Drift prediction
– Physical Management• Water cannon• Towing• Multi-vessel coordination• Towing in pack ice• Ice island
• Strategic– Data collection– Data fusion– Data management– Forecasting / threat
analysis / decision-making – Simulation training
Role of EO in Design and Operational Ice Management
• Sea Ice– Ice charts
• Encounter frequency from historical records• Tactical mapping as input into icebreaker support
– Ice regime characterization• First year/multiyear, thin/thick• Ice structure interaction
– Input to forecasting
• Icebergs– Historical aerial density– Population distribution– Drift speed assessment– Strategic and tactical surveillance
• Threat assessment and decision making• Input to drift tracking and forecasting• Supports iceberg physical management
Sea Ice from SAR
• Well known in the ice charting world
• Used for inversion of– Geophysical state: ice type,
concentration– Thermodynamic state
• Medium to low resolution SAR data are useful
– Significant quantity of data in satellite archive for historical quantification
• Multi-parameter SAR (frequency, polarization) more robust for charting
– Fewer ambiguities– More satellites mean more imaging
opportunities
• Available in NRT to support operational charting
– Both charts and image data are useful to ice management service providers
– Many imaging opportunities available in medium and low resolution
Open WaterFirst and Multi
Year Ice
New Ice
Land
L-Band C-BandL-Band C-Band
HV/HV/HH
Example – Historical Sea Ice Regime Characterization
Icebergs from SAR
• Icebergs appear as targets in SAR
• Detection probability a function of
– Iceberg size– Ocean state (wind)– Incidence angle– SAR resolution– Polarization
• Can use low resolution for population assessments
– Compensate for icebergs that are missed
• Available in NRT to support operational charting
– Higher resolution data required
• New SARs with better noise floor have high detection probability
TSX Data © Copyright ©2007 German Aerospace Center (DLR)/Infoterra GmbH
Iceberg Aerial Density from SAR
Ground Station
ENVISAT, RADARSAT-1/2, TSX, CSK
Internet
Level
1
Server
EOVAC
Server
Vessels/Platforms
Image Interp.
ChartQA/QC
Product
Data Fusion
DatabaseSatellite
MetIceOceanVAC
Elements of an Operational EO Service
ClientOps Centre
Client
Probability of Detection - RADARSAT-2
0.570.830.910.970.120.060.320.4320-25
0.950.990.900.380.530.7425-30
0.910.881.000.840.680.610.840.8730-35
0.790.900.820.780.760.930.9435-40
0.970.950.9740-45
15-2010-155-100-515-2010-155-100-5Wind Speed m/s
Incidence Angle
HVHHSCN Mode – 50 m
Medium Iceberg (50-120 metres)
0.740.881.001.000.320.240.520.6320-25
0.950.990.970.600.760.8725-30
0.920.920.990.940.880.810.930.9330-35
0.890.930.990.950.920.960.9635-40
0.950.950.9840-45
15-2010-155-100-515-2010-155-100-5Wind Speed m/s
Incidence Angle
HVHHFine Mode – 8m
Example of Surveillance Scenario
Aye Captain… land ho!!!
Is that an iceberg???