Figure 3. (a) A seismic section of prestack depth migrated data. Reservoir sands A, B and C are indicated on the gamma-ray curve. The poor bandwidth of the seismic data does not show the individual sands. (b) Equivalent section from absolute acoustic impedance. The upper dirty sand is seen with better definition. (c) Relative acoustic impedance calculated from thin-bed reflectivity derived from seismic data. The relative acoustic impedance section has done a better job of separating the stacked sands and reveals the basal part of reservoir sand C.