Abstract: Color Displays in Direct and Indirect Location of Hydrocarbons
Perhaps more than any other innovation since the invention of seismic prospecting, the process of digital recording and processing of seismic data has advanced exploration technology. It made possible economic processing and analysis of vast volumes of marine and land data, and has provided a greater degree of accuracy. More significantly, it also made possible the extraction of geologically and geophysically significant parameters from seismic data. These auxiliary variables have proved to be highly relevant to the direct and indirect location of hydrocarbons.
Pratt in the 1920s said that "the oil is found in the minds of men." It is indeed true that men through deductive reasoning must make the final judgement whether to drill and to test potential prospects. However, this reasoning must be supported by available geologic and geophysical evidence. It has been shown recently that most of this evidence is present on seismic sections and is obtainable through interpretation of the behavior of the auxiliary variables computed from the seismic data.
The significant features of basic tectonic and structural changes are predicted from the measurements of reflection times and velocities. The velocity and the reflection amplitudes provide ample information for a quantitative assessment of lithology, porosity, and fluid content. Frequently, continuity, and angularity of the seismic reflections give interpretive evidence of the depositional environment and stratigraphy.
The validity of the interpretation is enhanced substantially by the study of all of the auxiliary variables, particularly their anomalous behavior over the entire prospect. As a consequence the appropriate display of these variables and their relation to the basic seismic section is of utmost importance. Calibrated color displays suitably chosen, as well as the other forms of displays, allow rapid and quantitative correlation of auxiliary variables.
Examples are chosen from various geologic provinces with different exploration objectives. The significance of the variables relevant to their geologic interpretation is discussed.
AAPG Search and Discovery Article #90977©1975-1976 Distinguished Lectures