PHASE AND GROUP TIME SECTIONS AND POSSIBILITIES FOR THEIR USE IN SEISMIC INTERPRETATION OF COMPLEX MEDIA

Interpretation problems are discussed for a new class of models for complex seismic media, called heterogeneous models formed by inclusions (HMI). Examples of such models in geology are destructive deformation zones, tectonic raptures, complex folds, magmatogene formations, fronts of metamorphism and of phase transition, etc., which are of importance in interpretation of seismic data. The wavefields in such media have a complicated interferential character and should be considered as complex wave groups characterized by their phase and group properties. To study the phase and group characteristics of such wavefields, a method of construction and comparative analysis of so‐called phase and group sections is introduced. This method is based on a transformation of the wavefield (seismogram) into a normalized seismogram (cos of the phase) and a perigram (a low cut version of the trace envelope). The group sections obtained on the perigrams represent zones of energy concentration and give stable estimates of the average characteristics of model structure. The phase sections are obtained on the normalized seismograms and represent primarily, the inner structure of the model. The method was applied to both synthetic and field data. The results of the combined analysis of the phase and group sections show that in many cases there are significant differences between them. On the basis of this analysis, several types of seismic objects may be distinguished which can serve as a basis for seismic interpretation.