3-D PRESTACK EXAMPLE

The following example shows how to use SEPlib90 programs and libraries to analyze and manipulate 3-D prestack seismic data sets.

The data set is a single sail line belonging to a 3-D marine data set recorded in the North Sea. The data were recorded by shooting from two sources located at the stern of the recording ship into three streamers being pulled behind the ship. There are about 120,000 traces with 500 time samples in the data. The total size of the Data Values File is about 250 Mbytes. Figure  shows the source locations, for one trace out of ten in the data set. Figure  shows the receiver location for the same subset of traces in Figure . The receiver locations are scattered along the cross-line direction (y) because of a fairly strong cable feather, probably caused by ocean currents during acquisition. The corresponding CMP locations are shown in Figure . The cable feather caused a noticeable irregularity in the CMP coverage, with cross-lines overlapping in many places. Figure  shows the trace offset-azimuth distribution. Each of the six different trends distinguishable at small offsets corresponds to a source-streamer pair.

 

Sxy Figure 3 Source locations of data traces

 

Rxy Figure 4 Receiver locations of data traces

 

CDPxy Figure 5 CDP locations of data traces

 

OFFAZ Figure 6 Offset-azimuth of data traces