Figure 5.31: 4D repeatability: conventional data (left), reconstructed GeoStreamer data (middle) and the difference between the two to the right. The collocated sensors in the GeoStreamer make it possible to separate the seismic wavefield into up- and downgoing parts. These are independently re-datumed and summed (re-ghosted) to emulate the total pressure wavefield at the streamer tow depth used in the conventional survey. This means that the GeoStreamers may be towed at any depth in a 4D context.
Figure 5.32: Common shot gathers for vertical particle-velocity (left), pressure (middle) and processed up-going wavefield (right). Notice that the undulating behaviour of the receiver ghost is not present on the up-going wavefield.
