Based on the post-stack section below, shot in 1988, a reliable correlation of the two sub salt horizons, one beginning from 2600 ms at CDP 105 and another beginning from 2950 ms at CDP 105 could hardly be done for several parts of the section.

Hilbert transforms, coherent  and other kinds of filtering, and minimal-phase deconvolution programs of PMDI subsystem enabled to form Multi-D attribute which consisted of instant amplitudes, phases, frequencies and other transformed sections.

Classification program divided the section into 10 classes. As it is seen in the figure below, horizons can be traced with certainty for more than 90% of their length. Each horizon is characterized by a group of classes corresponding to its cover, porous zone and to the bottom which is identified at different sides of zones of lost correlation .