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| Source signature and static shifts estimations for multi-component ocean bottom data | |
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After obtaining the down-going wavefield, we can obtain an estimate of the source signature from the recorded amplitude of the direct arrival. Figure 9 shows several source wavelets at different offset values. For a near zero-offset wavelet, we can clearly identify the typical parts of a source wavelet, which include the source ghost and the source bubble. The amplitude of the large negative pulse is less than that of the large positive pulse. This fact indicates that the reflection coefficient of the water surface is not exactly -1.
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slices
Figure 9. Source wavelets at different offset values. These wavelets are obtained from the amplitude of the down-going wavefields windowed near direct arrival time. [ER] |
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In Figure 9, we see that the amplitude and shape of the source wavelet change drastically with the offset. Primary reflections overpower some of the source signals. The source bubble can hardly be identified.
Next, we compare our result with another source wavelet that is independently estimated in the same survey. We can see the difference in the large negative pulse and the source bubbles.
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compare
Figure 10. Comparison of our zero-offset source wavelet (solid line) with another wavelet independently estimated in the same survey (dashed line). Our wavelet indicates that the ocean surface reflection coefficent is not -1. Also, the amplitude of the source bubble is bigger. [ER] |
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| Source signature and static shifts estimations for multi-component ocean bottom data | |
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