Cepstrum decomposition of seismic signals and its application in hydrocarbon detection of ultradeep carbonate reservoirs
The cepstrum decomposition technology for seismic signals,recently developed for hydrocarbon detection,can highlight weak fluid information in some specific frequency bands of broadband seismic signals.This study explored the cepstrum decomposition tech-nology for seismic signals using Fourier transform(FT)-and wavelet packet transform(WPT)-based cepstrum.Moreover,the technology was applied to the ultradeep carbonate reservoirs in the Shunbei area for hydrocarbon detection.A comparative analysis was conducted on the characteristics of common cepstrum profiles and conventional common frequency profiles.Furthermore,a detailed comparative analy-sis was conducted on the characteristics of the first-and second-order common cepstrum profiles of FT-and WPT-based cepstra.On this basis,the hydrocarbon detection effects were compared between FT-and WPT-based cepstra.The processing results of actual seismic da-ta show that compared to the conventional spectral decomposition technology based on wavelet transform,the cepstrum decomposition technology manifested higher spatio-temporal resolution,providing more detailed information.Contrasting with FT-based cepstrum de-composition,WPT-based cepstrum decomposition provided a more accurate interpretation of gas-bearing properties through the seismic amplitude anomaly profiles.