Results

The shot gather shown in Figure  was first processed with the high-amplitude noise removal process shown in chapter  to produce the results in Figure . The value of w, the multiplier of the median, was 5 in this case. After the bad samples were removed, the inversion of system () was used to predict the noise and the missing data. The missing data was then added to the known data to produce a full set of data. This full set of data then had the noise subtracted from it to produce the signal section shown in Figure . The results in Figure  appear reasonable. The noise is well attenuated and the signal appears strong. Although the signal is not well predicted into the missing data area near zero offset, it has been extended several traces. Figure  shows the difference between the original data shown in Figure  and the calculated signal shown in Figure . While some signal appears in the difference section, it is weak compared to the noise. Some of this apparent signal may be due to differences in the coupling of each receiver's geophones to the Earth. Irregularities in the reflection amplitudes will be poorly predicted by the signal annihilation filter and will appear in the noise section.

 

original
Figure 1 A shot gather showing some bad traces and other noise.

 

mpatchs
Figure 2 The accepted samples from the data in the previous figure.

 

abmpatch
Figure 3 The signal extracted from the shot gather.

 

diff
Figure 4 The difference between the original data and the signal extracted.

Figure  shows the data from Figure  with the noise removal applied. Next, Figure  shows the data from Figure  where the inversion was used to predict the missing data while separating signal and noise, as in the previous Figures. Notice that most of the coherent noise discussed previously was not restored into the signal in Figure . Figure  shows the difference between the original data and the noise. Little signal has leaked into the noise section and the results appear satisfactory.

 

original2
Figure 5 A shot gather showing some bad traces and other noise.

 

mpatch2s
Figure 6 The accepted samples from the data in the previous figure.

 

abmpatch2
Figure 7 The signal extracted from the shot gather.

 

diff2
Figure 8 The difference between the original data and the signal extracted.