Figures & Tables
Seismic Stratigraphy Interpretation and Petroleum Exploration
During the past two decades, petroleum exploration has moved into frontier basins both onshore and offshore. Prospects in these basins have become increasingly deeper and often consist of potential deep-water reservoirs, in addition to more conventional shallow marine clastic and carbonate reservoir facies. By definition, frontier basins lack sufficient well control to permit conventional subsurface facies analysis and mapping. Consequently, the explorationist must extract maximum subsurface information from seismic reflection profiles. Without stratigraphic interpretation of frontier basins, exploration is limited to structural anomalies drilled without benefit of reservoir source or seal discrimination. Hence, concepts and techniques of seismic stratigraphic interpretation have developed to meet this need.
Integration of geophysical data with stratigraphic concepts has added a new dimension to basin analysis. Recent advancements ingeophysical data acquisition and processing, coupled with parallel advancements in depositional systems concepts, are responsible for the recent surge of interest in seismic-stratigraphic analysis. Two approaches to seismic stratigraphy have emerged during thelast decade: (1) a physical modeling of lithic and fluid composition utilizing computer analysis of velocity, amplitude, frequency, and other wave parameters; and (2) a stratigraphic/facies approach using reflection sections and geophysical logs (if available)to interpret lithofacies and, subsequently, depositional systems.Recognition of depositional systems on seismic profiles permits mapping of potential reservoir, source, and seal deposits, and provides the basis for reconstructing the structural, depositional, and erosional history of the basin. A depositional systems approach to seismic stratigraphy permits besin analysis using principally geophysical data.
Geologists generally need to improve their understanding of seismic geophysics and to work closely with geophysical interpreters.