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Metocean
Questions covered in this session
Metocean What is it all about?
How does Metoceanbenefit the oil & gasbusiness?
How big are Metocean 100 year design values?
How are Metocean data collected?
How does Metoceansupport Oil & Gas
Operations? Examples of where Metocean impacts the
Business
Objectives of this training module
To introduce you to Metocean Engineering and
its application in oil & gas
To motivate you to appreciate Metocean& findout how to improved design using Metocean.
After completion of this module, you will:
Be able to summarise what Metocean is all about and to
name the key metocean variables that affect design andoperations;
Have an overall picture of where Metocean Engineeringimpacts the business specifically as it relates to data
collection & Metocean input to engineering, safety andeconomics.
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Part 1: Metocean - What is it?
Sakhalin Molikpaq Platform in ice
Hurricane & Its Calling Card
Heavy Seas!
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Metocean and key metocean variables
Meteorological
WindsAir temperature
Air pressureHumidity
PrecipitationSuperstructure icing
Cloud cover/heightVisibilityDaylight hoursDust storms
Oceanographic
WavesCurrentsSea temperatureSalinityTide and water levelStorm surgeSea ice
Sea Spray icingIcebergs
Sediment transport
Metocean is about: describing the conditions, deriving design criteria,
providing operational statistics, and providing forecasts
Critical for both Design and Operations are adverse combinations of the above
The key deliverables
Information on the climate and
metocean environmentOperability and downtimestatistics
Forecasts of weather, wavesand currents
Design criteriaNumerical modeling of the
offshore environment and theresponse behavior ofstructures, floaters and
pipelines.
WAVES
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WAVE
SOUTH CHINA SEA TYPICAL DESIGN WAVE HT VS DEPTH
CURRENT PROFILE 1/7TH POWER
WIND
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The key application areas
Offshore fixed structures: platforms,jack-ups.
Offshore floating structures: FPSOs,
other floating productions systems,drilling rigs, barges, vessels, ships.
Pipelines (offshore & onshore).
Coastal planning and management:dykes, breakwaters, sewage outlets,hydrodynamic transport of
sediments, pollutants and oil spills.Coastal, river and land installations.
FPSO when is it safeto offload
The key sources of metocean info.
Literature searches National and international sources of data (government
agencies) Bespoke field metocean data collection campaigns Numerical modeling: hindcasting (i.e looking back in
time up to 50 or even 100 years) of winds, waves,
currents and water level
Numerical modeling: forecasting (looking ahead in timeup to 10 days or more and now also seasonally),primarily for weather, wave and water level conditions
but also increasingly for current conditions.
Part 2: How Metocean contributes to the business?
Fulmar Platform,
Central North Sea
Refining MetoceanDesignCriteria over the Field LifeCycle
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Metocean input to project life cylcle: Phase 1
Metocean input to project life cylcle: Phase 2
Metocean input to project life cylcle: Phase 3
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Metocean input to project life cylcle: Phase 4
Refine Metocean design criteria
Metocean input to project life cylcle: Phase 5
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Part 3: Metocean 100 year Design Values?
Squall-line over Port Hedland
Metocean conditions around the world
Definitions of Rough, Moderate and Mild
*N.B. The Sign ifi cant Wave Height value is approxi mately 54% of thecorresp onding Maximum Wave Heigh t (i.e. Hmax = 1.86 Hs)
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Metocean Categorisation by Area
Most likely sourse ofsevere events:S Extra tropical storms
E Earthquakes
C Hurricanes / Typhoons/Cyclones (winds/waves)M Monsoons (waves)I Ice
W Extra tropical storms (swell)R Currents
Metocean Categorisation by Area
Most likely sourse ofsevere events:S Extra tropical storms
E EarthquakesC Hurricanes / Typhoons/
Cyclones (winds/waves)M Monsoons (waves)I Ice
W Extra tropical storms (swell)R Currents
DESIGN WAVE & RETURN PERIOD
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Metocean Criteria Depends on Application
ISO 19901-1 - MetoceanDesign and Operating Cond
Further information: Metoceanconditionsaround the world then take a look at ISO19901-1 MetoceanDesign and OperatingConditions.
Metocean Design and Operating
Conditions in the ArcticAreas: Alaska, Canada, Caspian, Norway,RussiaEnvironment: Onshore, Deepwater, Heavy Ice, ShallowWaterMetocean Conditions: mostly Rough; some ModerateWinds: 30 to 40 m/s (58 m/s gust)Air Temperature: -50C to +43CWaves Hmax: 3 to 31 metresSurface Currents: 1.5 to 2 m/sWater Depth: North Caspian 4m +0.8m/-1.8mStorm Surge: +/-0.5 to 2 mSea Surface Temperature: -1.9C to +30CLevel Ice: 1.5m, Rafted Ice: 3m, Drift 2.5 m/s(Sakhalin)
First-year and Multi-year Ice (e.g. Alaska, Canada,Shtokman)Ridges & Hummocks: Sail 6m, Keel 26m, Gouging:1.6m (Sakhalin)
Stamukha: L=150m, W=40m, Thickness=11m(Sakhalin)Icebergs Scour: L=650m, W= 25m, D= average 0.3m(E. Canada)
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Part 4: Metocean Support to Operations.
Sakhalin MolikpaqPlatform in high waves
ApplicationsSurveys: Seismic & Sea bottom surveysDrilling:
Rig selection Logistics, Oil Spill Vortex Induced Vibration (VIV);Field Development Concept Selection:
Towage of structures to site
Installation of jacket, topsides, float-over, floatermoorings & risers, subsea equipment, pipelines
Production operations; e.g shuttle tanker offloading Marine and aviation logistics
Production Operations: Off-loading downtime Emergency MOB and Oil Spill Modeling / prediction Marine and aviation logistics Maintenance, e.g. diversAband on ment:
Weather window for abandonment operations
FPSO and Shuttle Tanker offloading
Main Metocean parameters
Winds (speed and direction) Waves (wave height, wave period, wave
direction) Currents (speed and direction over the whole
current profile) Meteorological Conditions n(fog, air
temperature, sea temperature)
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Metocean statistics
Monthly and seasonalpercentage exceedenceabove thresholds;
Monthly persistence statisticsabove and below thresholds forvarious durations;Variability in exceedence andpersistence statistics from oneyear to the next; distinguishingbetween a good year anda badyear.
Examples of Wind Rose and Monthly
Significant Wave Height Exceedence
Plots
Real-Time Metocean Data
are provided by:
Metocean stations
Remote systems on
Data Buoys
National network of
land and coastal
meteorological
stations
National data buoy
network
Weather and Ocean Forecasts
Forecasts are:
For3 to 7 days ahead
Area or site-specific
For aviation: specific format
Growing need for forecasts
of currents
Example Forecast P lots from Oceanweather.com
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Arctic Operational Issues
Summer Operations: Length of Summer Opr Window Variability in Onset of Thaw Early Freeze Up
Winter Operations: Variabili ty in Onset of Freeze Up Length of Winter Opr Window Icebreak: Ridges, Mult i-year ice Severity of Wint er (Impact onLogistics)
Fog: Impact on Helicopter Flights,Hovercraft and Marine Activities
Evacuation: In variety of adverse weather/iceconditions.
Arc tic Cond iti ons pro vi de ad ded
Dimension(s) to normal Operations
Part 5: How are Metocean Data collected?
Metocean Data Buoy
ready for deployment
Metocean Stations typical parameters
Wind speed, wind direction, atmospheric pressure, airtemperature, humidity, rainfall, visibility, cloud cover;
Significant wave height, maximum wave height, meanzero crossing period, peak period;
Profile (with depth) values of current speed, current
direction, temperature and salinity
Metocean Stations integrate the real-time collection,
processing, quality control, display, exporting (i.e.transmission) and archiving of meteorological andoceanographic information in one system. Typical
parameters are as below:
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Purposes of Metocean stations
Anemometer
Real-time information in support ofsafe and efficient operations (e.g.helicopter flights, drilling, heavy lifts,float-overs, etc.);
Near real-time information to theforecast agencies to improveaccuracy of forecasts;
Archive data for generating climaticstatistics for operational planning(i.e. downtime assessments) andmetocean design criteria.
Remote Deployments
Remote Deployment of Oceanographic Equipment
Numerical Modelling
Source: Oceanweather Inc. web site
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Satellite Data
Source:European Space Agency (ESA)
National Databases
Further information: US National Oceanographic Data Center archiv es
How Much MetoceanData are there in the Oil &
Gas Industry MetoceanData Bank?
World map showing areascovered by hindcastJ IPstudies.
Source:http://www.oceanweather.com/metocean/
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Weather and Ocean Forecasts
Part 6: Examples of where Metocean impacts
the business
North Caspian Off shore
Metocean Station
How Metocean contributes to Business 1
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How Metocean contributes to Business 2
METOCEAN