Abstract: A method is disclosed for characterizing the subsurface levels of the Earth with a greater degree of accuracy than hitherto. Seismic data samples are migrated and stacked, for example according to known techniques and then spectrum analyzed. The spectrum analysis is applied to a feature of the subsurface and, for example, a particular layer bounded by a pair of horizons would be subject to volume reflection spectral analysis. The analysis is carried out using an orthogonal base by defining the reflection signals in terms of coefficients to a set of orthogonal polynomials. Additional seismic characteristics or attributes may be directly calculated from the polynomial coefficients. These coefficients represent the characteristics of the layer to a high degree of accuracy and may be compared with spectra derived a priori (for example, synthetic spectra or previously characterized spectra) to further assist in analysis of measured seismic data.

Abstract: A plurality of seismic traces are arranged in order of increasing of feet and features therein are analyzed so as to identify corresponding features in each of the curves. The travel time to each of the features is derived in order to extract an actual travel time curve as a function of offset.