RELATIONSHIPS BETWEEN DEPOSITIONAL FABRIC AND RESERVOIR QUALITY DISTRIBUTION IN MICROBIAL REEF RESERVOIRS, LITTLE CEDAR CREEK FIELD, CONECUH COUNTY, ALABAMA

The relationship between microbial depositional fabrics and reservoir quality distribution is examined in the Jurassic Smackover Formation at Little Cedar Creek Field in southwest Alabama. Previous studies of Smackover microbial fabrics at other oil fields in the eastern Gulf Coastal Plain have indicated a relationship between syndepositional microbial texture and porosity/permeability of the hydrocarbon reservoirs. However, these microbial buildups have been shown to develop directly on Paleozoic paleohighs. Conversely, Little Cedar Creek microbial buildups are shown to develop in shallow subtidal environments without the influence of a rockground substrate.

This study compares the relationship between depositional fabric and reservoir quality between Little Cedar Creek Field and two fields representative of microbial development on rockground substrate (Appleton and Vocation fields). Such a comparison can be used to refine exploration and development strategies for microbial reefs.

This study will improve the understanding of Upper Jurassic Smackover microbial development, its lithologic fabrics and controls on reservoir quality (porosity and permeability distributions). The results will serve to refine the conceptual models for exploration of other microbial carbonate reservoirs. Examining the controls on reservoir quality distribution at Little Cedar Creek will provide new insights into this unique and prolific petroleum reservoir facies.