Print this pageStratigraphy and Reservoir Characterization of an Exhumed Oil Field on the Eastern Flank of the Valles-SLP Carbonate Platform (Albian-Cenomanian), Tampico-Misantla Basin, Mexico
KOZAR, MICHAEL G., WILLIAM M. FITCHEN, and DONALD A. YUREWICZ
Measured stratigraphic sections of the El Abra Formation from quarries in the Sierra de El Abra provide the data base for investigation of the sequence stratigraphy and reservoir characterization of a large exhumed oil field on the eastern flank of the Cretaceous Valles-San Luis Potosi platform in east-central Mexico. This field serves as an analog for the prolific accumulations of the Golden Lane and Poza Rica trends in the subsurface, and for potential undiscovered fields in central Mexico.
Measured sections were used to create a sequence stratigraphic framework and to characterize the depositional architecture, diagenesis, and reservoirs within this exhumed oil field. Three composite sequences are recognized in a reef margin to platform transect. The composite sequences are comprised of thirteen high-frequency sequences. The high-frequency sequences can be subdivided into transgressive systems tracts and highstand systems tracts based on parasequence stacking patterns, facies proportions, and facies offsets. This stratigraphic hierarchy appears to be the primary control on reservoir heterogeneity as exhibited by the distribution of oil staining. In general, "reservoir units", are defined by composite sequence boundaries, whereas "flow units" are defined by high-frequency sequence boundaries and parasequence boundaries. Parasequences and their component lithofacies influence the distribution of flow barriers and flow baffles, and as such, define "flow zones". Karsting associated with Laramide uplift and erosion can further compartmentalize the reservoir.