Imaging through gas with four-component, 3D-Seismic data

Imaging below gas is a robust application of four-component (4C) seabed sei smic, Imaging of faults and the crest of the structure under the gas cloud have been improved. Conventional streamers record only the pressure (P)-wav es and suffer from very-low signal/noise ratio and pull-down under the gas cloud. P-waves converted to shear (S)-waves, PS-waves, are largely unaffect ed by fluids. Multicomponent methods have been developed, including normal moveout (NMO), dip moveout (DMO), and binning, to improve converted wave pr ocessing, The migrated pressure wave images show good imaging of the steep flank segments, distortion under the gas-invaded zone, and poor event conti nuity in the crestal feature. The converted wave images show similar struct ure and good continuity under the gas.