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Metocean Committee 2002-4 activities. Chris Shaw Chairman OGP Metocean Committee Shell International E&P. Metocean Committee. Application of (new) metocean technology in the (offshore) oil and gas industry Balance economic benefits with appropriate safety margins

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Metocean Committee 2002-4 activities

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Metocean committee 2002 4 activities

Metocean Committee 2002-4 activities

Chris Shaw

Chairman OGP Metocean Committee

Shell International E&P

Metocean committee

Metocean Committee

Application of (new) metocean technology in the (offshore) oil and gas industry

Balance economic benefits with appropriate safety margins

Develop standards and guidelines

Meets twice/year, in Europe and USA

Metocean committee 2002 4 activities1

Metocean Committee2002-4 activities

Metocean committee 2002 4 activities

West Africa Swell Project (WASP)

  • Better discrimination of low frequency end of wave spectrum is one of most pressing problems for design and analysis of floating systems

  • Floating systems very sensitive to peak periods and the shape of the spectrum

  • West Africa is particularly important area

Development of a swell event offshore nigeria

Development of a Swell Event offshore Nigeria

Development of a swell event at bonga

Development of a Swell Event at Bonga

Wasp project status

WASP: Project status

  • Seven participants signed up

  • Data assembled - being processed to calculate directional spectra and partition into sea and swell components

  • Preliminary results in May 03; Final in Q4 03



  • Comparison of Measurements and Hindcasts

  • Scatter Plots of Hs and Tp

  • Joint Environmental Contours

  • Shape of the Swell Peak in the Power Spectrum

  • Directional Characteristics of Swell

  • Response Spectra

  • Stationarity of the sea state

  • Infragravity Waves

Ocean turbulence measurements

Ocean Turbulence Measurements

  • Almost no full scale data on turbulence scales of interest

  • Spar Responses on 60 - 600 seconds are of interest

  • Associated Turbulence Scales are about 60 - 600 m

  • Current turbulence data typically is on the scale of 10s to 100s of km, or on very small (mm) scale.

  • 15 min current averaging is standard… all turbulence information of interest is lost!

  • Ocean Model Basins have difficulty generating low turbulence currents

Metocean committee 2002 4 activities

Ocean Turbulence Measurements

Deepstar turbulence program

DeepStar Turbulence Program

  • Workshop held in Houston November 6-7/02

  • Strategies for measurement program identified

  • Request for planning letters sent to interested investigators

  • Field program planned this year, results in Q1/04

Adcps ct sensors on towed fish rgl victoria bc

ADCPs & CT sensors on towed fish (RGL Victoria BC)

Squall measurement and analysis project

Squall Measurement and Analysis Project

winter storm


Squalls are short-lived

but intense

Squalls are


Squalls tend to form along lines

Metocean committee 2002 4 activities

  • Determine the mooring line size for spread moored FPSOs offshore West Africa

  • Pose an operational hazard for connecting tankers to CALMS and FPSOs offshore West Africa

  • Determine the maximum offset for floating production systems offshore West Africa

  • Pose a potential fire hazard due to lightning strikes

P rincipal knowledge gaps

laterally coherent gust

laterally uncorrelated gust

Principal knowledge gaps

  • Lateral coherence of gusts is unknown

  • Assume gusts longer than 1 minute are coherent over the entire length of an FPSO or tanker (conservative?)

P roposed project



Proposed project

  • Jointly funded industry project (uniform industry-wide database and procedures)

  • Two-year measurement program at EDOP

  • Measurements with fine resolution in time and space

  • Squall climate at EDOP should be similar to that at Bonga.

    • expect 25+ days with significant squall events

    • expect at least 10 events with winds > 20m/s

Metocean committee 2002 4 activities

The EDOP flare bridge is an ideal “open structure” 370 m long

Metocean committee 2002 4 activities


30 m

24 m

27 m

21 m

18 m

  • Measure horizontal coherence with 5 sensors over 250 m

  • Measure vertical profile over most critical elevation range

  • High sample rate (1Hz) to resolve all pertinent time scales

  • Doppler weather radar to track squall lines

Metocean committee 2002 4 activities


Existing structure


Added cross piece



Cross-sectional view of bridge with notional set up of instrument masts

Metocean committee 2002 4 activities

Original Schedule

  • Jun2002- select consultants, make reconnaissance trip

  • Jul 2002- issue ITT to bidders

  • Aug 2002- select contractor

  • Sep 2002- submit firm proposal to OPTS

  • Oct2002- declare project a “go” and award contract

  • Jan2003- install instruments

  • Dec2004- complete measurements

  • Mar2005- complete analyses and deliver report

Safety guidelines for metocean surveys

Safety Guidelines for metocean surveys

  • Issues:

    • Reduce near-misses while working on vessels

    • Sea-worthiness of vessels of opportunity

    • Provide level playing field for suppliers

    • Help improve standards for companies without metocean engineers

  • LIP financed by 6 oil companies

  • Developed jointly with companies and suppliers

  • In final form, ready for publication as OGP document later Q2/03

Metocean committee activities 2002 4

Metocean committee activities 2002-4

Metocean committee activities 2002 41

Metocean committee activities 2002-4

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