Major new discoveries, both onshore and offshore, are fueling continued interest in Upper Jurassic rocks of the eastern Gulf Coast. This report provides a comprehensive geological study which integrates stratigraphic, geochemical, petrographic, petrophysical, and production data for these rocks in eastern Mississippi, southwestern Alabama, and the Florida Panhandle.

     This regional study, representing approximately 10 man-years of geologic research, focuses on the exploration and production potential of the Smackover along the Gulf Rim from the eastern part of the Mississippi Salt Basin to the Apalachicola Embayment. The study area encompasses all or portions of 49 counties and approximately 28,000 square miles in Mississippi, Alabama, and Florida.

     More than 12,000 feet of cores from 89 Smackover wells were described. This information is integrated into the stratigraphic framework for this study. Approximately two-thirds of these cores are proprietary.

     Approximately 1,500 thinsections from 60 wells were examined. A classification of grain types based on petrographic characteristics and grain size was developed for the Samckover. A summary of this classification is included in the report. This summary provides industry with the first attempt to describe and document photographically all the major types of non-skeletal grains found in the upper Smackover. Differentiation of the types of coated grains in the Smackover is a cornerstone for

interpreting the depositional environments of these rocks.

     Fifteen stratigraphic markers were correlated which have sub-regional and regional importance to Smackover exploration. Markers are defined from the base of the Cotton Valley Group to the Louann Salt or basement.

     Stratigraphic correlation of the 2,273 study wells provides a unique database. It provides a three-fold system for regional analysis of Smackover and Haynesville rocks. This analysis is based upon a combination of lithologic and chronostratigraphic markers and log facies characterization. A comparison of these data yields a basin-wide model for Smackover basin evolution, depositional style, and timing of salt and fault movement.

    Selected fields for study include Blacksher, Nuxford, Chatom, Blackjack Creek, and Nancy fields. Each field study contains development geology and engineering analyses including evaluations of reservoir drive mechanisms, key well panels showing lithologic and fluid saturation computations, reserve evaluations, and well performance reviews.

     Organic geochemical analyses were acquired on 1,116 source rock samples throughout the study area. These analyses of source potential and thermal maturity data were incorporated into a stratigraphic context. From this information, source rock maturity trends were mapped.