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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 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 Develop standards and guidelines Meets twice/year, in Europe and USA
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
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
Analyses • 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 • 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
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
Squall Measurement and Analysis Project winter storm squall Squalls are short-lived but intense Squalls are thunderstorms Squalls tend to form along lines
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
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?)
Bonga EDOP 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
The EDOP flare bridge is an ideal “open structure” 370 m long
radar 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
mast Existing structure guys Added cross piece mast guys Cross-sectional view of bridge with notional set up of instrument masts
Original Schedule • Jun 2002 - select consultants, make reconnaissance trip • Jul 2002 - issue ITT to bidders • Aug 2002 - select contractor • Sep 2002 - submit firm proposal to OPTS • Oct 2002 - declare project a “go” and award contract • Jan 2003 - install instruments • Dec 2004 - complete measurements • Mar 2005 - complete analyses and deliver report
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 Not the end - other issues?