Geometry of acquisition

The 3D dataset consists of 20 sail lines each with four active streamers and dual flip-flop shooting. The separation between streamers is 160 m and between receivers is 25 m. The shot interval is 37.5 m (between the flip and the flop). The minimum offset inline is 240 m and each streamer has 288 receivers for a maximum inline offset of 7175 m. Figure  shows the acquisition template. Figure  shows a map view of the subset of the shots used in this study. Although most sail lines were straight in the East-West direction, a few had significant curvature.

 

acq_sktch1
Figure 1 Sketch of the basic acquisition geometry

 

shots_map
Figure 2 Map view of the source locations.

The strong currents present in the area caused significant feathering. Figure  shows an example for the sail-line at cross-line distance 11440 m. For most shots, the feathering was in the same South-North direction. Figure   shows the fold of coverage that in some places depart significantly from its design value of 48. Some of the short source lines in Figure  we acquired as infill to avoid large coverage holes.

 

feathering
Figure 3 Map view of the receiver cables for one shot illustrating typical feathering.

 

fold
Figure 4 Fold map illustrating relatively uniform coverage.