Integrated Geological, Geophysical, and Computer Approach for Predicting Reef Lithofacies and Reservoirs: Upper Jurassic Smackover Formation, Appleton Field, Alabama

Abstract

Reefs have long been known from the Upper Jurassic Smackover Formation in the Gulf Coastal Plain; however, these carbonate lithofacies have unique acoustic properties that make them difficult to define using 3-D seismic reflection technology. In the eastern Gulf Coastal Plain, microbial reef buildups occur on pre-Jurassic paleotopographic basement features on a carbonate ramp margin. Development of these buildups is a result of the interplay among paleotopography, sea-level changes, and carbonate productivity. An integrated approach of geological interpretation, computer modeling, and seismic imaging indicates that Smackover reef development is restricted to the flanks of high-relief structures, whereas on low-relief structures reef development occurred on both the crest and flanks. The combination of geological and computer modeling of parameters affecting reef development associated with pre-Jurassic paleohighs in conjunction with 3-D seismic imaging increases the chances of drilling a successful exploration well and in designing an effective field-scale reservoir management strategy.