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Town and Gown Mathematics Department,
Covenant University
Ota, Nigeria
Applied Mathematics in the Oil & Gas
industry: Metocean Engineering
Dr. Emmanuel Osalusi, CSci, CMarSci
Senior Metocean Engineer The Shell Nigeria Exploration and Production Co.
Lagos, Nigeria
1 05/11/2017
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Covenant University
Vision Statement:
To be a leading World-Class Christian Mission University,
committed to raising a new generation of leaders in all fields of
Human endeavour.
Mission Statement:
To create knowledge and restore the dignity of the black man via
a Human Development Total Man Concept driven curriculum
employing innovative, leading-edge teaching and learning
methods, research and professional services that promote
integrated, life-applicable, life-transforming education,
relevant to the context of Science, Technology and Human
Capacity Building’ 2 05/11/2017
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Applied Mathematics
Applied Mathematics:
a combination of mathematical science and specialized knowledge
Beyond numbers
Uncertainty Quantifications. e.g.
1. ….they were about 600k men on foot, besides women and children (Exo.
12:37)
2. …and they that did eat were 5000 men, besides women & children - Mathew
14:21
3 05/11/2017
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OUTLINE
1. Safety moment
2. Background
3. Introduction to Metocean Engineering
4. Metocean Considerations for Offshore Oil/Gas Development
5. Specifying the Offshore Environment
6. Metocean and its implications for offshore design and operations
1. Impact on Design Criteria
2. Impact on Operations
7. Q&A
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Safety Moment
5 05/11/2017
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Institutions Attended
Academic
Qualifications
PhD Petroleum Engineering (Institute of Petroleum
Engineering, Heriot-Watt University, UK)
MSc Applied Mathematics (University of Limpopo, South
Africa
PgDip, Mathematical Sciences, (African Institutes for
Mathematical Sciences – www.aims.ac.za ), University of Cape
Town, South Africa
BSc (Hons), Mathematical Sciences, Ondo State University
(now Ekiti State University, Ado-Ekiti), Nigeria
Professional
Qualifications
Lead Auditor /Auditor Course, Quality Management System
(ISO 9001:2008)
Member, The Institute of Marine Engineering, Science &
Technology (MIMarST - UK)
PRINCE2 – (Project Management - UK)
Chartered Scientist (CSci), Science Council (UK),
Chartered Marine Scientist (CMarSci), IMarEST (UK)
QUALIFICATIONS
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Year Institutions Attended
1997 - 2000 Computer Officer/QA&QC officer, SPIE Enertrans S.A., Nigeria.
Shell/Total/NNPC LNG contract, Bonny Island, Rivers State.
2000 - 2001 Document Control Officer, Titan Engineers & Constructors, Nigeria.
Shell/Total/NNPC LNG contract, Bonny Island, Rivers State.
2001 - 2002 Administrative Officer/Document Control Officer, Hyundai Heavy
Industries, Nigeria, Shell/Total/NNPC LNG contract, Bonny Island,
Rivers State.
2006 Research Associate, International Centre for Theoretical Physics
(ICTP), Italy (CNR-ITAE).
2006 - 2009 Research Associate, Heriot-Watt University, Edinburgh.
2009 - 2010 Numerical Hydrodynamic Engineer, Total Gas & Power Ltd.,
London
2010 - 2011 Senior Oceanographer, Partrac Ltd., Glasgow
2011 - 2013 Senior Global Analyst, GE Oil & Gas, Newcastle, UK
2013 ongoing Senior Metocean Engineer, SHELL, Nigeria
CAREER PATH
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Peer Reviewed Publications
1) E. Osalusi, J. Side, R. Harris. Structure of turbulent flow in EMECs tidal energy test
site, Int. Comm. Heat and Mass Transfer, 36, 5,422-431, (2009)
2) E. Osalusi, J. Side, R. Harris. Reynolds stress and turbulence estimates in bottom
boundary layer of Fall of Warness, Int. Comm. Heat and Mass Transfer, 36, 5, 412-
421, (2009)
3) E. Osalusi, J. Side, R. Harris. Thermo-Diffusion and Diffusion-Thermo effects on
combined heat and mass transfer of a steady MHD convective and slip flow due to a
rotating disk with viscous dissipation and Ohmic heating, , Int. Comm. Heat and Mass
Transfer , 35, 908-915 (USA), (2008)
4) E. Osalusi, J. Side, R. Harris. Ohmic heating and viscous dissipation effects on
unsteady hydromagnetic flow and heat transfer over a porous rotating disk with variable
properties, hall and ion-slip currents, Far East Journal of Applied Mathematics, In
press, (2008) etc
5) ( 17 – Fluid Mechanics, 2 on Oceanic Turbulence)
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Metocean Engineering
9 05/11/2017
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Metocean Engineering and the business
The impact of metocean engineering applies across all phases with the
potential to add value at each phase ([Opportunity Realisation Process
(ORP) phases]
10
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High cost of getting metocean wrong
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Marine
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Aviation Nigeria: 322 fatalities in about a 14 months
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Squalls: formation
LiVe IMAGE
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Aviation: Turbulent wind - Squalls
http://www.sat24.com/foreloop.aspx?type=1&continent=afrika
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Aviation: Squalls
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Airfrance 477: 228 fatalities – all lost!
X
The aircraft encounters point X, where it enters the microburst zone, and a headwind causes
it to rise above the normal glideslope. At the center of the microburst, point Y, there is a
downdraft causing the aircraft to sink. The aircraft now enters the most dangerous zone,
point Z, where a sudden tailwind causes the aircraft to lose airspeed and potentially crash.
F-7-14-54 (AF477)
Y
Z
Microburst zone Most dangerous zone
2:14:28 Hrs 2:06 Hrs
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The cost of getting it wrong!
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Metocean = Meteorological + Oceanographic
What is metocean
Abbreviation came in 40 years
ago
Metocean is a discipline covering
meteorology and physical
oceanography, and is concerned
with quantifying the impact and
effect of weather and sea
conditions on a wide range of
activities in the onshore and
offshore oil & gas and renewables
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Metocean
Metocean = meteorological + oceanographic
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The role of Metocean Engineer
Provide optimal/suitable and innovative Metocean solutions and guidance for
offshore/onshore projects:
Extreme design criteria for ultimate strength
Fatigue criteria
Operational criteria for construction/tow/installation
Meteorological and oceanographic instrumentation and measurement
systems
Weather and ocean modeling and forecasting
Renewable ocean/wind energy
Ice management planning
Iceberg and sea ice tracking
Research/technology development
Industry/regulatory liaison 20 05/11/2017
http://sww.wiki.shell.com/wiki/index.php/File:KANUMAS_Ice_Breaker_Odin.bmphttp://sww.wiki.shell.com/wiki/index.php/File:Groundediceberggreenland3.JPG
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Engineering Requirements
Metocean Conditions
Metocean Data
Acquisition
Weather Forecasts/ Hindcasts
Metocean Design
Criteria & Operational Statistics
Metocean cycle Challenges
• Cross-discipline awareness
• Early interaction
• Appropriate time & budget for deliverables
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Institute of Petroleum Engineering, Heriot-Watt
University, UK
Research works
Ocean Turbulence – Wave-Current Interactions
22 05/11/2017
There is no branch of mathematics, however abstract, which may not
some day be applied to phenomena of the real world. Nikolai Lobachevsky
http://www.azquotes.com/quote/586908?ref=applied-mathematicshttp://www.azquotes.com/quote/586908?ref=applied-mathematicshttp://www.azquotes.com/quote/586908?ref=applied-mathematics
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Motivation
23 05/11/2017
goal
…the understanding of the flow
due to short-term fluctuations in
stream velocity, at a typical tidal
stream site, will assist in the
modelling of a tidal test site and
improve design optimisation of
tidal stream turbine design.
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Inline force
t
XρVCX(t)|X(t)|ρAC(t)F mdx
2
1
'uUX
Morison’s Equation
2'''
2
1||
2
1)( UAC
t
uVCuuACtF dmdx
Oscillatory Force Steady Force oscillatory drag coefficients
24 05/11/2017
Inertia Force Drag Force
'''
cw uuu
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Ocean turbulence
Multimodal directional seas
affects stability,
fatigue loading and
response
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Boundary layer
26
Uc
CBL
MWS
Uw
h
0 WBL w
Boundary-layer-induced turbulence fluctuations:
Creates unequal forces on the turbine
Cyclic loads on the blade
Fatigue damage
Excitation of roll response
In physics and fluid
mechanics, a boundary
layer is the layer of fluid
in the immediate vicinity
of a bounding surface
where the effects of
viscosity are significant.
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Boundary layer
27
Interaction btw WBL & CBL creates transient &
nonlinear flow ….. transient load
CBL
WBL
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Boundary layer
28
The ability of the offshore structure to cope with short-term stream velocity variations such as those resulting from turbulence or wave–current interactions is a concern in
offshore industry
'uUX
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Turbulence
w
wc
c
Total Bed Shear Stress = Mean Bed Shear Stress + Maximum Oscillatory Bed Shear Stress
2
2
ln130
ln12
2
1
b
A
Nc
ccc
k
k
ek
h
f
uf
29 05/11/2017
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Analysis Method – Flow Chart
30 05/11/2017
ADCP Raw
Data
Pytho
n
Raw Binary
Waves Data
Raw
Binary
Current
Data
Turbulence
Estimates
Prime Flowchart
Preprocess
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Directional
Wave
Spectra Input
Record Length [FN: RunDirSp, specCompute2]
Compute: Cross Power
Spectrum Wavenumber
Transfer parameter
Directional Spectra Wave
parameters (Hs, Tp, DTp, Dp) [FN: specCompute3, specCompute4]
Plotting:
S(f,Q), Hs, Tp, DTp,
Dp [FN: specPlot1, specPlot2]
Save:
S(f,Q), Hs, Tp, DTp, Dp [Folder: waveplots_{starting date} ]
[FN: specCompute2]
Directional
Wave Spectra
Smooth?
Smooth Spec
with
resolution Yes
No
Preprocess
Analysis Method – Flow Chart
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Raw
Current Data
Structure of Measured Data
+
Configuration [FN: runCurrent1]
Plotting:
*10-min mean current velocity Vs time
*Water level Vs mean (over depth) current velocity
*Depth-time current velocity magnitude
*Tidal height Vs time [FN: runCurrent2]
Current Profiles Preprocess
Analysis Method – Flow Chart
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Raw
Current Data
Structure of Measured Data
+
Configuration [FN: runCurrent1]
Plotting:
*10-min mean current velocity Vs time
*Water level Vs mean (over depth) current velocity
*Depth-time current velocity magnitude
*Tidal height Vs time [FN: runCurrent2]
Current Profiles Preprocess
Analysis Method – Flow Chart
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QC: Data must undergo extensive quality control analysis in order to ensure that the
uncertainties in the output are reduced to the minimum.
Before the deployment
thresholds are set in order to ag bad data
that fall outside of broad error specifications or against a narrower range of error
specifications
Error due to strong reflections from the water surface that overcome the sidelobe
suppression
Pre-processing
some data may be questionable.
Such suspected data, called spikes, are not removed; rather, they are detected
and possibly replaced.
Spikes in the data may corrupt, overestimate wave spectra or skew smoothed
estimates. Spikes in the ADCP data are mainly caused by fish, ship, turbulence and
floating debris.
Data QC – Noise Removal
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Data QC – Noise Removal
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(1) Detecting
(2) Removing
(3) Replacing erroneous data
Methods:
1. Acceleration Threshold Methods
2. Phase-Space Threshold Method (PTM) (3D
Poincare map Method)
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Data Quality Control
36 05/11/2017
2222
Dumt
Voulgaris & Trowbridge
(1998)
Sampling error related to
Phase shift (independent
of flow)
Error variance due
to mean velocity
shear (flow related)
Doppler noise related to
Doppler band width
broadening (flow related)
Total vel. Error
variance
[dominate noise term
due to turbulence and
the mean shear error,
becomes significant
close to the seabed]
The total source of
noise in ADCP
beam
velocity is given as:
ADCP=Acoustic Doppler Current Profiler
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3D Poincare Method
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These methods are based on the
observation that the derivative of a signal
amplifies the high-frequency components
(the spikes domain). The separation of
these erroneous data is amplified as the
order of derivative increases.
),(),(
),(),(),(
tt
t
ttXty
j
j
k
j
kkk
=Fourier series transformed of u(t) – instantaneous velocity,
w(t) the radial frequency and j positive index
),( tk
)sin(22
2
tt
)cos(
)sin(
tt
t
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3D Poincare map
Method
38 05/11/2017
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TKE- Reynolds stress
39 05/11/2017
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Metocean Considerations for Offshore Oil &
Gas Development Projects
40 05/11/2017
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Field development concept selection
Offshore Field Development Concept Selection influenced by: • Field characteristics • Water depth • Metocean conditions……
41 05/11/2017
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Fixed platform
Limited to ~ 300 m Piled steel jacket & concrete gravity platform
Loading: waves and currents on substructure winds on topsides
Deck elevation Sufficient air gap to allow for wave crests, tide & storm surge
Scouring Near bed currents
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Towing and installation
Metocean Impact on: Installation method Barge selection Design of sea fastenings Tow route
Hazards Long period waves Wave height Cross seas Strong currents Wind/wave/current offsets
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Floating production systems Various Types: TLP, Semi-Sub, Spar, FPSO
Advantages over fixed structures Deep water Small fields/short field life Re-use other location
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Floating production platform
Metocean needed for: Feasibility appraisal Floater selection, modification or new design Product export – tanker offloading or pipeline Subsea installation Floater installation Operation Decommissioning/re-use Cost Benefits: Metocean + Response Based Design For feasibility & selection of appropriate system Metocean statistics for vessel motion, Operational windows for FPSO shuttle tanker Metocean conditions Assessment of fatigue life
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Subsea, pipelines & cables
Metocean Hazards: Strong near-bed currents Wave motions (shallow water) Seabed scouring Unsupported spans Bottom temperatures Turbidity currents Hydrate formation Ice
46 05/11/2017
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Jetty Coastal Protection
Marine Cooling Water and
Desalination Systems Coastal Facilities
Coastal facilities
47 05/11/2017
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Offshore operations
Applications: Offshore Oil & Gas Production Aviation Marine vessels Oil spill contingency
Metocean deliverables: Metocean Operational Planning Statistics Real-Time Metocean Measurements Weather Forecasts Oil spill modeling and contingency plan
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Metocean requirements for each development phase
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Metocean desktop study process map
Deliverables
Technical Review
(TA Sheet)
Request
Define SOW,
Approaches and
deliverables
Report
Memo
Data Sources
Analysis
Assign TA/TR
Brief the work
Q/A
Status
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Data sources
Sea Surface
Seabed
300khz ~ 100m range
75khz ~ 500m range
38khz ~ 1000m range
Seabed or BOP-mounted 75khz ~ 500m range
RovADCP ~ 6000m range
51 05/11/2017
http://www7320.nrlssc.navy.mil/GLBhycom1-12/navo/globalsshnowcast.gif
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SQUALL
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SOLITONS
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Metocean data consideration
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Metocean data consideration - annual variation
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Design criteria – design philosophy
Goal: design offshore facility to withstand extreme environmental conditions that will
occur during its lifetime with “optimum” risk level
Weigh consequences of failure against cost of over-designing
For facilities with 20-30-year lifetime, generally use 100-year metocean criteria
With typical implicit and explicit safety factors, annual probability of failure ≈ 10-3 to 10-4
Procedure:
Analyze historical environmental conditions
Assume future exposure will have the same statistics of extremes as past exposure
Global climate change:
Effect on extreme conditions is not yet known, and is generally neglected
Assume design safety factors will accommodate any increase in environmental severity
that may occur
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SPECIFYING THE OFFSHORE
ENVIRONMENT
57 05/11/2017
Applied mathematics will always need pure
mathematics just as anteaters will always
need ants. Paul Halmos
http://www.azquotes.com/quote/1255760?ref=applied-mathematicshttp://www.azquotes.com/quote/1255760?ref=applied-mathematicshttp://www.azquotes.com/quote/1255760?ref=applied-mathematicshttp://www.azquotes.com/author/28949-Paul_Halmoshttp://www.azquotes.com/author/28949-Paul_Halmos
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Structural response to extreme conditions
58 05/11/2017
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Marine operability assessment
59 05/11/2017
Measurement
Modeling (hindcasting)
Continuous time-series
Acceptable motions criteria
Analysis (available windows)
Modeling (berthing simulator)
Modeling (vessel responses)
Metocean Environment
Vessel particulars
Floating System
Basin testing
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Side-by-side offloading
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FENDERS
MOORING LINES
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Solitons impact
Impact
Fatigue – risers, subsea equipment
Operations – ROV
In mathematics and physics, a soliton is a self-reinforcing solitary wave
packet that maintains its shape while it propagates at a constant velocity.
1. It must maintain its shape when it moves at constant speed.
2. When a soliton interacts with another soliton, it emerges from the
"collision" unchanged except possibly for a phase shift.
61 05/11/2017
https://en.wikipedia.org/wiki/Mathematicshttps://en.wikipedia.org/wiki/Physicshttps://en.wikipedia.org/wiki/Wave_packethttps://en.wikipedia.org/wiki/Wave_packet
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Metocean delivers a broad range of products
Example Product Delivery List
Seismic data acquisition criteria
Drilling criteria
Rig orientation
Riser fatigue
Mooring criteria
Host/Site design criteria
SURF design criteria
Tow criteria
Installation/construction criteria
Waiting on Weather statistics
Environmental sensors for MAS/MIS
62 05/11/2017
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THE METOCEAN CHALLENGE
Risk
Costs
Risk
Costs
Improvements through:
63 05/11/2017
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OCEANOGRAPHIC PARAMETERS FOR DESIGN
Criteria need to address
multiple parameters in space
and time
Wind, wave, and current are
vectors with magnitude and
direction
Wind/wave have broad
frequency components
Some conditions drive
ultimate strength, some drive
fatigue
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Characterizing random seas
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Conclusions
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The cost of getting it wrong !
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68
The cost of getting it wrong !
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The cost of getting it wrong !
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High cost of getting metocean wrong
71 05/11/2017
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“If you stop at general math, you’re only going to
make general money.” – Snoop Dogg
Thank you!!
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