Seismic sequence analysis and attribute extraction using quadratic time‐frequency representations

Abstract

The variation of frequency content of a seismic trace with time carries information about the properties of the subsurface reflectivity sequence. As a result, analysis of the data in terms of the local frequency content can provide a worthwhile addition to the standard procedures that are used in seismo‐stratigraphic interpretation. The theory of quadratic time‐frequency representations provides a solid foundation for local frequency analysis of seismic data and seismic attribute extraction. Two applications of the quadratic time‐frequency representations are demonstrated: seismic sequence analysis and seismic attribute extraction. The joint time‐frequency representation of a seismic reflection pattern is often much more easily interpreted in terms of subsurface stratification than the time‐or frequency‐domain description alone. We show how the time‐frequency representation can be used to delineate seismic sequences on the basis of the time‐frequency characteristics of the signal. There exists a close relation between complex‐trace attribute analysis and quadratic time‐frequency representations. In the time‐frequency approach, the seismic attributes are characteristics of the local spectrum. Extraction of the attributes from the time‐frequency representation of the seismic trace leads to considerable improvement of the signal‐to‐noise ratio of the attributes. Furthermore, the classic set of seismic attributes of instantaneous amplitude, phase, and frequency can be easily extended with other parameters describing the local spectrum, such as instantaneous bandwidth, skewness, and kurtosis.