Dip-consistent Interpolation of Seismic Prestack and Poststack Data Into Mute Zones Using CRS Techniques

Near-surface mute zones hamper the derivation of near-surface velocities, and degrade the near-surface image. Operator noise at mute edges may obscure the near-surface image after migration. In order to avoid such problems an interpolation method for prestack and poststack data is proposed using the Common-Reflection-Surface (CRS) method. The dip-consistent interpolation takes advantage of the CRS attributes which provide a highly detailed description of the seismic wavefield including the lateral continuation within a CMP aperture. CMP/offset regularisation and prestack data interpolation are then performed simultaneously during partial CRS stacking into so-called CRS gathers. In addition to a strong signal enhancement and better offset coverage, this partial stacking defines a new mute function in the CRS gathers. The live data is thus extended into mute zones within the CMP aperture of the CRS processing. Stacking or prestack migration transfers this interpolation to poststack domain. Applications in prestack and poststack domain show a good continuation of flat and dipping events. The increased zone of live data, and the improved offset coverage of the CRS gathers, may be be exploited for a fine-tuning of near-surface velocities, and thus for a better focusing and resolution in near-surface imaging.