ABSTRACT

The frequency-weighted-exponential (FWE) function was designed to fit various asymmetric amplitude spectra by two parameters: symmetry index and bandwidth factor. A relation can be built between the FWE function and the Q-factor of media. When a source wavelet propagates in attenuating media, the FWE function is used to fit the amplitude spectra of the source and attenuated wavelet to obtain the symmetry indexes and bandwidth factors. After recalculating the bandwidth factors based on the average of the symmetry indexes, the Q-factor can be estimated by the decrease in the bandwidth factor between the source and attenuated wavelet. Compared with the existing commonly used methods, this method applies to various source wavelet types, and it has better tolerance to random noise. On this basis, we further evaluated an approach to invert the interval Q-factor from seismic reflection data. We used the FWE function to fit the local spectral contents of the interval seismic reflection data to obtain the symmetry indexes and bandwidth factors. After recalculating the bandwidth factors with the average of the symmetry indexes, the reciprocal of the bandwidth factor versus traveltime was linearly fit, and then the Q-factor can be calculated from the slope. This approach has high accuracy without having to correct for the tuning effect when the attenuation is high. It is suitable for different types of synthetic seismic traces and also produces good results in a field-data case study.

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