Page 362 - Acquisition and Processing of Marine Seismic Data

6.8 SHAPING FILTERS 353

FIG. 6.38 Poststack Burg deconvolution application. Stack sections (A) before, and (B) after Burg deconvolution
(n ¼ 40 ms). Corresponding amplitude spectra and autocorrelograms are given in the top and bottom panels, respectively.

i. Time durations of zero phase wavelets are Therefore, a conversion from minimum
shorter than their minimum phase phase to zero phase is commonly applied to
equivalents of the same amplitude spectra. the marine seismic data during data processing
This property causes the zero phase wavelets and is known as dephasing. The wavelet in the
to have higher resolving power. seismic data is converted to a zero phase wavelet
ii. While the onset of a minimum phase with an amplitude spectrum the same as that of
wavelet coincides with the horizon, the the input wavelet. Fig. 6.40 shows an example
main positive lobe of a zero phase wavelet application to zero phase conversion of a mini-
exactly coincides with the stratigraphic mum phase stack section. Note that the seabed
interface, which makes the horizon picking reflection is located at 170 ms, which corre-
easier and more convenient if the data is sponds to the onset time of the minimum
zero phase. phase wavelet and the main lobe is located at