UPPER JURASSIC-LOWER CRETACEOUS ROCKS OF THE SOUTH FLORIDA BASIN: AN UPDATE TO UNDERSTANDING THEIR STRUCTURE, THICKNESS, AND RESERVOIR QUALITY

Rocks of Late Jurassic and Cretaceous age in the South Florida Basin (SFB) consist of thick carbonate units associated with various shallow-water marine environments that commonly contain and are separated by evaporite beds of varying thickness. In many cases, these relatively thick carbonate-evaporite sequences contain reservoir-quality porous rock that is sealed by surrounding gypsum, anhydrite, or low-permeability micritic limestone. In the past decade, these porous rocks have piqued the interest of various industries, as they could contain trapped petroleum or alternatively could serve as storage reservoirs for anthropogenic carbon dioxide. This study presents an update to the current understanding of the thickness and extent of these rocks throughout the SFB, some of which have never been mapped, and characterizes reservoir quality, based upon recent data collection from publicly available geophysical logs that were compiled over the last 30 years. Specifically, isopachs, isoliths, and porosity and net-porous distribution maps are presented here for the Lower Cretaceous Dollar Bay Formation, Brown Dolomite Zone and Twelve Mile Member of the Lehigh Acres Formation, Pumpkin Bay Formation, and Bone Island Formation, as well as the Upper Jurassic Wood River Formation. Since all but one of these stratigraphic units occur below the producing horizon of the petroleum-rich Lower Cretaceous Sunniland Formation, exploration and characterization of these rocks often did not occur in any great detail prior to this study, with the exception of several Lower Cretaceous studies conducted in the 1970s and 1980s. As such, this study marks one of the few detailed characterizations of the Lower Cretaceous and Upper Jurassic rocks within the SFB.