Gulf of Mexico Basin, Alabama Ayobami .T. Folaranmi* and Jack Pashin. Boone Pickens School of Geology, Oklahoma State University, Stillwater Oklahoma *[email protected] The purpose of this study was to characterize a saline formation that is actively being used to store CO 2 as part of the SECARB III Anthropogenic test in Alabama. The study is aimed at understanding the potential of Lower Cretaceous redbeds to store commer- cial quantities of anthropogenic CO 2 . Citronelle Dome is a simple salt-cored anticline that lacks faults and contains abundant reser - voir sandstone bodies and mudstone, evaporite, and carbonate seals. The Paluxy Formation has an average thickness of about 1,100 feet in Citronelle Dome. Core analysis indicates that the Paluxy Formation is a coarsening-upward, succession composed of numerous stacked, aggradational sandstone-mudstone packages. In- Three wells were drilled for injection, monitoring, and reservoir characterization. Cores from the Paluxy were retrieved, and a full suite of open-hole geophysical logs was acquired. Detailed petrologic and well log analysis was performed to analyze frame- work sandstone composition, sandstone diagenesis, and reservoir architecture. High porosity and permeability in the sandstone units facilitate high CO 2 capacity and injectivity, and multiple reservoir seals ensure safe permanent storage in Citronelle dome. Sandstone body geometry is complex, and understanding reservoir heterogeneity is an essential component of reservoir manage- ment in Citronelle Dome. CHOCTAW CLARKE WASHINGTON MOBILE BALDWIN Citronelle Dome Wiggins Arch Hatchetigbee anticline Mobile Graben West Bend Fault Gilbertown Graben ALABAMA MISSISSIPPI MISSISSIPPI INTERIOR SALT BASIN PLANT BARRY CITRONELLE FIELD Index Map 0 i m 0 2 0 1 10 EXPLANATION Citronelle Field C red power plant (~14 MMst CO 2 /yr) Normal fault; bar on downthrown side Fold; arrow points in plunge direction 0 10 20 30 km 10 Research Supported by Advanced Resources International through grants from the U.S. Department of Energy and Southern Company CONCLUSIONS STUDY AREA GEOPHYSICAL LOGS PETROLOGY MODERN BRAIDED FLUVIAL SYSTEM ANALOG CORE PHOTOGRAPHS Well D-9-8 #2 The Paluxy Formation was deposited in continental environments that Petrographic analysis indicates that the sandstone units are composed of arkose to quartzarenite. Porosity and permeability are well-developed in the sandstone, with values commonly exceeding 20% and 200 mD. Provenance analysis indicates that most of the detritus originated in transitional continental to craton interior settings. Many Cretaceous sandstone units in the eastern Gulf Coast resemble the Paluxy Formation at Citronelle, indicating exceptional storage capacity exists in the Cretaceous redbeds of the region. ABSTRACT Quartzarenite Subarkose Sublitharenite Arkose Arkosic litharenite Lithic arkose Litharenite Q F L 25 50 25 25 5 Craton interior Basement uplift Quartzose recycled Transitional recycled Lithic recycled Mixed Dissected arc Transitional arc Undissected arc 23 47 13 11 42 29 20 43 Transitional continental Qm F Lt Classification Thin section photomicrograph Core Plug Analysis Plot SEM Photographs Provenance Intraclastic conglomerate Cross-bedded sandstone Ripple cross-bedded sandstone Burrowed sandstone Red mudstone Calcareous mudstone Core width = 10 cm Washita- Fredericksburg interval Paluxy Formation Ferry Lake Anhydrite Donovan sand Mooringsport Formation GRAPHIC CORE LOGS 9620 9610 9580 9590 9600 9570 ft 9630 Sandstone Mud vf f m c Cgl Sandstone Mud vf f m c Cgl Sandstone Mud vf f m c Cgl Sandstone Mud vf f m c Cgl D-9-7 #2 9450 9440 9410 9420 9430 9400 ft 9460 D-9-8 #2 Core 1 10450 10440 10430 ft 10460 Braided channel Braided channels Braided channels Longitudinal bars Longitudinal bars Longitudinal bars Longitudinal bars Longitudinal bars Longitudinal bars Braided channels (vertisol, sheet- Vertisol Vertisol Vertisol Vertisol Vertisol Vertisol D-9-8 #2 Core 2 Ganges River, India 9440 9410 ft 9420 9430 D-9-9 #2 Mudstone Sandstone Intraclastic conglomerate Roots Caliche Horizontal laminae Cross-beds Pebbles Ripples Rock type Color Sedimentary structure Meniscate burrows Pedogenic Slickensides Very Dusky Red Dusky Red Dark Red Weak Red Pale Red Light Reddish Brown Pale Brown Very Pale Brown Gray Inter- D-9-7 #2, 9624.5 ft D-9-7 #2, 9624.5 ft D-9-7 #2, 9570 ft D-9-7 #2, 9570 ft D-9-7 #2, 9568 ft D-9-7 #2, 9568 ft D-9-9 #2, 9424.5 ft D-9-9 #2, 9424.5 ft D-9-8 #2, 9449 ft D-9-8 #2, 9449 ft D-9-7 #2, 9634 ft D-9-7 #2, 9634 ft Quartz overgrowth Pore-filling Kaolinite Euhedral quartz overgrowth Carbonate rhomb Illite-lined pore Grain-size pore Vacuolized feldspar Illite coat D-9-7 #2, 9595.60 ft D-9-7 #2, 9621 ft D-9-8 #2, 9439.50 ft D-9-8 #2, 9401 ft REGIONAL GEOLOGY CO 2 Capture Plant Facility D-9-7 #2 Injector Well Structural contour map Top Ferry Lake Anhydrite Stratigraphic column of saline formations and seals Shale Limestone and Chalk Anhydrite Sandstone and conglomerate EXPLANATION Bashi Marl Hatchetigbee Sand Selma Group Wilcox Group Midway Group Salt Mountain Limestone Porters Creek Clay Claiborne Group Jackson Group Oligocene Miocene Pliocene Citronelle Formation Pensacola Clay Eutaw Formation upper Tuscaloosa Lower Tuscaloosa marine shale Paluxy Formation Mooringsport Formation Washita- Fredericksburg interval Pilot sand massive sand Dantzler sand Ferry Lake Anhydrite Lower CRETACEOUS Upper Paleocene Eocene Oligocene Miocene- Pliocene Lithology Geology 2000 Depth (ft) 11000 10000 9000 8000 7000 6000 5000 4000 3000 1000 0 Tuscaloosa Group Tallahatta Formation TERTIARY MESOZOIC CENOZOIC Proven injection zone Carbon Sequestration Target Interval Protected water Proven injection zone Potable water Locally potable water Saline formations below 2000 ft Regional seal Regional seal Regional seal Regional seal Regional seal Proven injection zone -10500 -10500 -10500 -11000 -11000 -11000 -11500 -11500 -12000 -12500 -13000 -12000 -12500 T. 3 N. T. 1 W. T. 2 W. T. 3 W. T. 4 W. T. 2 N. T. 1 N. T. 1 S. T. 2 S. T. 3 S. 0 5 mi 0 10 km > -10500 ft (-3.2 km) -10500 to -11000 ft (-3.2 to -3.4 km) -11000 to -11500 ft (-3.4 to -3.5 km -11500 to -12000 ft (-3.5 to -3.7 km) -12000 to -12500 ft (-3.7 to -3.8 km) -12500 to -13000 ft (-3.8 to -4.0 km) < -13000 ft (-4.0 km) Normal fault; bar on downthrown side Citronelle dome Anticline; arrow indicates plunge Syncline; arrow indicates plunge CD CD Hatter's Pond fault Contour interval = 100 ft HPF HPF Pilot area Longitudinal Interfluve Interfluve Braided channel 0.5 mi complex bars