EVALUATION OF DEEP SALINE AQUIFERS OF SOUTH-CENTRAL AND SOUTHERN FLORIDA FOR GEOLOGIC CARBON SEQUESTRATION AND ENHANCED OIL RECOVERY

Concerns about elevated atmospheric carbon dioxide (CO₂) and the effect on global climate have created proposals for the reduction of carbon emissions from large stationary sources, such as power plants. Carbon dioxide capture and sequestration (CCS) in geologic formations is being considered by Florida electric utilities. Carbon dioxide-enhanced oil recovery (CO₂-EOR) is a form of CCS that could offset some of the costs associated with geologic sequestration. Two potential reservoirs for geologic sequestration were evaluated in south-central and southern Florida: the Paleocene Cedar Keys Formation/Upper Cretaceous Lawson Formation and the Lower Cretaceous Sunniland Formation along the Sunniland Trend (Trend). The Trend is a slightly arcuate band in southwest Florida that is about 233 kilometers long and 32 kilometers wide, and contains oil plays within the Sunniland Formation at depths starting around 3,414 meters below land surface, which are confined to mound-like structures made of coarse fossil fragments, mostly rudistid reefs. The Trend commercial oil fields of the South Florida Basin have an average porosity of 16% within the oil-producing Sunniland Formation, and collectively have an estimated storage capacity of around 30.5 million tons of CO₂ (MtCO₂). The Sunniland Formation throughout the entire Trend has an average porosity of 14% and an estimated storage capacity of about 914 MtCO₂. The Cedar Keys Formation/Lawson Formation storage zone has an average porosity of 22% and an estimated storage capacity of nearly 50 billion tons of CO₂. The Cedar Keys Formation/Lawson Formation and Sunniland Formation storage zones are potentially suitable for CCS operations because of their geographic locations, appropriate depths, high porosities, estimated storage capacities, and effective seals. The Trend oil fields are suitable for CO₂-EOR in the Sunniland Formation due to appropriate injected-CO₂ density, uniform intergranular porosity, suitable API density of formation-oil, sufficient production zones, and adequate remaining oil-in-place following secondary recovery. Geologic CCS has not yet been conducted in Florida, and its implementation could prove useful to Florida utility companies, as well as other energy utilities in the southeastern United States.