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On the Oceanography of 
Brazil’s Equatorial Margin: 
Hazardous Offshore Currents 
and Strategies for Mitigation 
Dave Frat...
Conclusions 
• Brazil’s Equatorial Margin has both extraordinary development 
opportunities and significant operational ch...
Outline 
• Geographic Context and Operational Challenges 
• Oceanographic Environment 
• Strategies for Mitigation
Image 
Geographic Context 
BEM potential may be 
similar to West Africa 
Zaedyus find in 
French Guiana is 
encouraging 
C...
Total 
Quieroz Galvao 
BP 
BHP Billiton 
Quieroz Galvao 
BG 
BP 
OGP 
BHP Billiton 
ExxonMobil 
Chevron 
BP 
OGP 
BHP Bill...
• Tides and tidal currents 
• River outflow 
Intense, persistent, and 
vertically-complex 
boundary current 
Sensitive hab...
• Tides and tidal currents 
• River outflow 
Intense, persistent, and 
vertically-complex 
boundary current 
Sensitive hab...
Operational Challenges 
Image 
ENSCO 8503 
Tullow 
French Guiana 
• Remote location 
• Extensive coastline with 
sensitive...
Oceanographic Environment 
Image
SeaWiFS Ocean Color 
Image 
Satellite observations are descriptive – but not always quantitative.
12 years of surface drifter trajectories (n=450) 
Color = Current Speed
Image 
Why surface drifters? 
• Direct measure of surface 
velocity, exchange processes 
• Analog for anything drifting at...
Image 
Histogram of all drifter-derived current 
measurements in each BEM region
Average measured 
current speed as a 
function of WATER 
DEPTH 
Gray dots are all 
measurements
Average measured 
current speed as a 
function of WATER 
DEPTH 
Gray dots are all 
1000 m measurements
1/3-deg Gridded log(NDATA) 
Number of hourly velocity 
estimates from drifter 
position record
1/3-deg Gridded Current Velocity
Image 
Numerical Ocean Model 
VELOCITY (kts)
Models are ALWAYS wrong
Models are ALWAYS wrong
Models are ALWAYS wrong 
Models can be useful if constrained 
and validated by observations 
We must know HOW the model is...
Strategies for Mitigation 
To mitigate the impact of strong ocean currents and 
operate successfully in the equatorial mar...
A regional observation and prediction system 
Observations Model Forecast
A regional observation and prediction system 
Image 
• In-situ measurements of ocean currents 
• Inexpensive 
• Sustainabl...
A regional observation and prediction system 
• Seismic Survey 
• Engineering Design 
• Installation 
• Diving 
• ROV Oper...
Observation System Status: 18 Sep 2014
Observation System Status: 18 Sep 2014
Observing System Summary 
• Surface drifters have been deployed 
in the BEM about every two weeks 
since July 2014 
• Surv...
Conclusions 
• Brazil’s Equatorial Margin has both extraordinary development 
opportunities and significant operational ch...
Image 
Thank you 
Dr. David M. Fratantoni 
Horizon Marine, Inc. 
Massachusetts, USA 
dave@horizonmarine.com 
Mr. Andre Gel...
On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation
On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation
On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation
On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation
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On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation

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By Dave Fratantoni, Andre Gellers, and Neha Sharma

Published in: Environment
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On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation

  1. 1. On the Oceanography of Brazil’s Equatorial Margin: Hazardous Offshore Currents and Strategies for Mitigation Dave Fratantoni, Andre Gellers, and Neha Sharma Horizon Marine, Inc. Massachusetts, USA
  2. 2. Conclusions • Brazil’s Equatorial Margin has both extraordinary development opportunities and significant operational challenges. • Strong and variable ocean currents are a primary concern. • Exchange between blue-water and coastal regimes is poorly Image Image understood. • A regional ocean observing and prediction system can provide improved situational awareness to mitigate the impact of strong currents on offshore operations, enhance safety, and protect the environment.
  3. 3. Outline • Geographic Context and Operational Challenges • Oceanographic Environment • Strategies for Mitigation
  4. 4. Image Geographic Context BEM potential may be similar to West Africa Zaedyus find in French Guiana is encouraging Coastline is extensive, sensitive
  5. 5. Total Quieroz Galvao BP BHP Billiton Quieroz Galvao BG BP OGP BHP Billiton ExxonMobil Chevron BP OGP BHP Billiton OGP Ecopetrol ExxonMobil Petrobras
  6. 6. • Tides and tidal currents • River outflow Intense, persistent, and vertically-complex boundary current Sensitive habitats
  7. 7. • Tides and tidal currents • River outflow Intense, persistent, and vertically-complex boundary current Sensitive habitats
  8. 8. Operational Challenges Image ENSCO 8503 Tullow French Guiana • Remote location • Extensive coastline with sensitive ecosystems • Strong and variable ocean currents • Poorly understood connections between offshore and coastal regimes Holding station with 90% thrust
  9. 9. Oceanographic Environment Image
  10. 10. SeaWiFS Ocean Color Image Satellite observations are descriptive – but not always quantitative.
  11. 11. 12 years of surface drifter trajectories (n=450) Color = Current Speed
  12. 12. Image Why surface drifters? • Direct measure of surface velocity, exchange processes • Analog for anything drifting at the ocean surface • Excellent for model validation • Easy to deploy from a variety of platforms • Inexpensive  robust statistics
  13. 13. Image Histogram of all drifter-derived current measurements in each BEM region
  14. 14. Average measured current speed as a function of WATER DEPTH Gray dots are all measurements
  15. 15. Average measured current speed as a function of WATER DEPTH Gray dots are all 1000 m measurements
  16. 16. 1/3-deg Gridded log(NDATA) Number of hourly velocity estimates from drifter position record
  17. 17. 1/3-deg Gridded Current Velocity
  18. 18. Image Numerical Ocean Model VELOCITY (kts)
  19. 19. Models are ALWAYS wrong
  20. 20. Models are ALWAYS wrong
  21. 21. Models are ALWAYS wrong Models can be useful if constrained and validated by observations We must know HOW the model is wrong, and WHEN it can be trusted
  22. 22. Strategies for Mitigation To mitigate the impact of strong ocean currents and operate successfully in the equatorial margin we require enhanced situational awareness, specifically: • Accurate measurement of currents TODAY • Accurate forecast of currents TOMORROW
  23. 23. A regional observation and prediction system Observations Model Forecast
  24. 24. A regional observation and prediction system Image • In-situ measurements of ocean currents • Inexpensive • Sustainable • Spatially diverse • Family of appropriate numerical models • Global and regional blue-water ocean models • Coastal models with accurate tidal and river forcing • Local oil spill models for incident response
  25. 25. A regional observation and prediction system • Seismic Survey • Engineering Design • Installation • Diving • ROV Operations • Pipelaying • Incident Response
  26. 26. Observation System Status: 18 Sep 2014
  27. 27. Observation System Status: 18 Sep 2014
  28. 28. Observing System Summary • Surface drifters have been deployed in the BEM about every two weeks since July 2014 • Surveys utilizing expendables (CTD, SV, CP) expected to begin in early 2015 • Regional 1/32o model run daily – working on drifter data assimilation • Interpretive reports generated weekly
  29. 29. Conclusions • Brazil’s Equatorial Margin has both extraordinary development opportunities and significant operational challenges. • Strong and variable ocean currents are a primary concern. • Exchange between blue-water and coastal regimes is poorly Image Image understood. • A regional ocean observing and prediction system can provide improved situational awareness to mitigate the impact of strong currents on offshore operations, enhance safety, and protect the environment. • A prototype observing and prediction system is operational TODAY
  30. 30. Image Thank you Dr. David M. Fratantoni Horizon Marine, Inc. Massachusetts, USA dave@horizonmarine.com Mr. Andre Gellers Horizon Marine do Brasil Rio de Janeiro, Brasil andre@horizonmarine.com

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