Steffen, Kelley¹, Gene Rankey¹, Ralf Weger¹, Mark Grasmueck¹, Don McNeill¹ 
(1) University of Miami, RSMAS, Miami, FL

ABSTRACT: Using High-Resolution Ground Penetrating Radar to Investigate the 3-D Sedimentologic Architecture of the Pleistocene Miami Oolite

The Pleistocene Miami Oolite is a carbonate ooid sand shoal with complex and heterogeneous internal architecture. Full-resolution imaging using 3-D ground penetrating radar (GPR) data provides the means to map details of sedimentary structure and to improve existing flow models. To explore facies architecture, a 24x46 meter, dense (10x20 cm) 3-D GPR survey grid was integrated with cores from the survey area. Collectively, these provide physical property data (of both depositional and diagenetic origin) of the oolitic geobody. 
Results show that the heterogeneity of this ooid shoal system is influenced by bedform stratigraphy and cross-cutting dissolution features. Interpreted 3-D migrated data show complex internal bedform structures, including migrating sand waves, foreset truncations and bifurcations, mottled facies, and possible karst features. Scanning the animated time slices shows variations in amplitude, continuity, and orientation of reflectors, interpreted in the context of abrupt changes in bedding geometry within the unit. 
Sedimentologic features identified in cores provide calibration points for high resolution, three-dimensional interpretation of the geobody. Such a model allows for submeter scale analysis of connectivity and distribution of individual units and can lead to more accurate flow models for similar heterogeneous systems. Further test sites on the Miami Oolite are under investigation to establish regional variations in spatial architecture that could be applied to oolitic reservoirs.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.