Resumo

CORRALES, Álvaro; CABRERA, Francisco  e  MONTES, Luis. Enhancing time resolution by stabilized inverse filter and Q estimated on instantaneous spectra. Earth Sci. Res. J. [online]. 2014, vol.18, n.1, pp.63-67. ISSN 1794-6190.  https://doi.org/10.15446/esrj.v18n1.36056.

Physical phenomena, such as attenuation of high frequency components and velocity dispersion, deteriorate seismic images. To enhance seismic resolution, Q filtering is usually applied, where the accurate estimation of Q is the core of this approach. The Matching Pursuit (MP) approach is an instantaneous spectral analysis method that overcomes windowing problems caused by decomposing a seismic trace, providing a frequency spectrum for each time sample of the trace. By changing variables, the spectra is transformed into a new domain where Q is accurately measured. This value is input to a stable inverse Q filter, which solely compensates for the amplitude without distorting the phase, and as a result, an improved time-resolution image is obtained. MP, windowed Fourier (WF), and Gabor transforms (GT) were tested on synthetic seismograms providing Q values that indicated the best performance of MP. Applied to a migrated offshore Colombian seismic line, the entire procedure coded in Matlab compensated for the energy losses and increased the S/N ratio. The trace-by-trace approach guarantees the reliability of the improvement in the continuity of seismic events and is applicable to pre-stack data as well.

Palavras-chave : Inverse filter; quality factor; spectral analysis; instantaneous spectrum; attenuation.

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