Utilizing Gabor Deconvolution to Improve Resolution in the Image Domain

Gabor deconvolution, an extension to nonstationary Weiner deconvolution, was utilized as a post- depth migration processing filter to determine its benefit for improved resolution and multiple attenuation in the image domain. Tests were carried on pre-stack depth-migrated 2D gathers on deep offshore data. The geology of the region combines complex salt tectonics with layers of evaporative sequences (LES). The LES sequence generates short-period multiples which are difficult to attenuate using velocity-based algorithms.

Traditional deconvolution compensates for absorption through its assumption of ”white” reflectivity spectra, with most of the implementation therefore implying an infinite ”Q” attenuation function. In contrast, the nonstationary approach to the deconvolution process approximates the values associated with the attenuation function ”Q”. We expect, therefore, that the nonstationary approach should be more suitable in the presence of the complex velocity where the assumption of an infinite ”Q” would provide suboptimal results (i.e., failure of the underlying assumption of Stationary Deconvolution). We performed a series of tests which applied Gabor deconvolution in the image domain in order to suppress multiples and to balance reflection amplitudes. We established a systemic approach to test this method by applying Gabor either before or after a velocity-based multiples attenuator. Results were then compared as controlled group against each other through spectral analyses

Application of the Gabor deconvolution in the image domain resulted in the recovery of frequencies between 20-40 Hz and the slight suppression of low frequency noise between 0-10 Hz. As a result we obtained a laterally well-focused stacked section with preferable amplitude balancing. A validation study was undertaken in order to compare our results with those obtained from the conventional predictive deconvolution. Our final results showed an overall improvement in resolution, better continuity of the reflections and suppression of multiples in several zones.

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