Page 302 - Acquisition and Processing of Marine Seismic Data

5.7 TRACE EDIT 293

FIG. 5.56 The effect of turning of the streamer behind the vessel when entering a survey line. (A) A number of shots from
the beginning of a seismic line, recorded in the course of a streamer’s turn, which result in curved disruption zones, indicated
by blue arrows. (B) Same shots after killing the far offsets with curved arrival times (blue arrows). After shot number 123, the
streamer finishes its turning and becomes straight.

and narrows with increasing shot number, since and shooting proceeds during the vessel’s turn
the streamer becomes straighter and straighter at the end of the line.
along the line. After shot number 123 in In modern seismic data processing, manual
Fig. 5.56A, it seems that the streamer becomes editing of the traces and shots is definitely
straight again. These curved areas have incorrect impractical since the large seismic datasets,
reflection arrival times and should be completely especially 3D data volumes, contain thousands
removed from the data. Fig. 5.56B shows the shot of shots and millions of traces, and it is impossi-
gathers after killing the far offset traces with ble to examine all available traces of such data-
incorrect arrival times. These disruption zones sets manually in a feasible time period, even
may also occur at the end of the survey lines if for an experienced processor. Therefore, specific
the run-out distances are not fully considered algorithms are developed that automatically