Multi 4 Component Seismic (4C)

Four-component (4C) seismic data are typically acquired using three orthogonally-oriented geophones or accelerometers and a hydrophone within an ocean-bottom sensor. The system can be deployed in node-type systems or as cables. The addition of geophones/accelerometers allows measurement of shear (S) waves, as well as compressional (P) waves.

4C seismic has a number of potential advantageous over conventional seismic:

Improved Imaging

• Imaging through gas clouds and gas charged sands where the P wave image is blurred, noisy, non existent or distorted, 4C can illuminate previously hidden prospects and reservoirs
• Imaging weak P impedance contrast (transparent) reservoirs
  
• Imaging where there is a strong P multiple, by better survey geometry, a broader frequency band and dual sensor summation
• Imaging beneath salt and imaging in complex structural areas to improve illumination and resolution of sub-salt prospects

Improved Lithology/Fluid prediction in reservoirs

• Bright Spot anomaly analysis
• Reservoir characterization for exploration pre-drilling and delineation phase through seismic attributes (Vp/Vs etc.)
• Lateral extent of oil bearing sands away from well control
• Saturation mapping

Seismic Anisotropy (Directionally dependent) determination

• Estimating Vertical Transverse Isotropy (VTI) parameters for use in processing
• Fracture density and direction; optimize drilling campaigns for field development and production phase through the use of the full azimuthal coverage
  

4C Seismic can potentially therefore:

• Produce clearer pictures of complex Oil and Gas fields
• Provide more information about reservoir rocks
• Reduce development risks and enhance Oil recovery

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