Wavelet Processing
Spectrum uses the stand alone ‘Nucleus’ Wavelet Processing software in order to design dephasing and designature operators, etc.
a) Take a number dump of the recorded far field signature with acquisition filters applied and find the minimum phase equivalent of this signature. A matching filter is then derived which converts the signature to its minimum phase equivalent, this filter is then applied to the data.
b) A signature is extracted from the data using a program that extracts a wavelet from each trace within a user defined derivation window. This program separates the wavelet from the trace by using Taner's exponential decay method. Once the wavelet is extracted, an operator is computed to convert it into any user-desired waveform. The wavelet can be mixed with the ones from neighbouring traces to improve its stability.
Post-Stacka) Take migrated data from close to a well location and create an average seismic trace over a zone of interest. Using the sonic and density logs from the well a reflection coefficient series is created and a wavelet which best matches the RC series to the seismic is extracted. This wavelet is then used to derive a dephasing filter which can be applied to the seismic data. In practice the Hampson Russell “ELOG” software is used. The method is described in Hampson & Galbraith 1981.
b) Statistical method as for pre-stack wavelet processing.
Resources:
- Taner, M. T., and Coburn, K. W., 1980 - Surface consistent estimation of Source and receiver response functions: Presented at the 50th Annual International SEG Meeting, November 18, Houston.
- Hampson & Galbraith 1981 - Wavelet extraction by sonic log correlation. Canadian Journal of Exploration Geophysics Vol. 17 pp 24 - 42.
