Extracting wavelets
Traces are extracted into zero-phase wavelets using the following process:
During extraction, all import traces are summed and the resulting trace tapered.
Next the import trace is auto-correlated and an operator is extracted from the center. This is likely a non-zero operator at the operator extremities and must therefore also be tapered using either Cosine, Hanning, or Cosine Squared methods. The longer the extracted operator, the more detailed the extraction. You may want to extract the wavelet using long operators (high detail), then shorten the wavelet length after to avoid damaging the amplitude spectrum detail. GeoSyn saves only the amplitude and phase spectrums and calculates time wavelets when required.
Lastly, an amplitude spectrum is calculated from the extracted, tapered wavelet. The phase spectrum is set to zero.
To extract wavelets:
1. From the Edit menu, select Wavelet
(
).
The Wavelet
dialog box appears.
2. Beside the Extractionlabel, click Extract.
The Import time data dialog box appears.
3. Select the SEGY file with data upon which to base the extracted wavelet then click Open.
The Zero Phase Extraction Processing
Flow
dialog box appears.
4. Specify the time range and number of traces to sum, the method by which to sum the traces, the length of operator to derive from the summed traces, and the method by which to taper the operator, and then click OK.
The extracted wavelet appears in the Wavelet Properties dialog box.