3-D Vision Ground Penetrating Radar (GPR): Reservoir Anatomy Beyond the Outcrop Surface

Mark Grasmueck¹, David Viggiano¹, Langhorne Smith², and Richard Nyahay^2
1 University of Miami, RSMAS, Miami, FL
² New York State Museum, Albany, NY

Conventional outcrop observations, digital photography, laser scanning and remote sensing can capture only the characteristics of exposed geology. This superficial information is biased by the extent, geometry and quality of the accessible rock faces. In contrast, full-resolution 3D Ground-Penetrating Radar (GPR) imaging non-destructively extracts the missing information at submeter resolution from inside the rock volume.

The objective of the 3D GPR survey in the Palatine Bridge limestone quarry (NY) was to delineate the rubble covered part of the fractured and hydrothermally altered reservoir analogue. We recorded the 3D survey grids with a 0.05 m x 0.10 m spacing using 250 MHz GPR antennae. The 3D cubes precisely define the floor plan of a buried en-echelon fault geometry in map view. Such precise geometric information would not have been obtained with a conventional grid of e.g. 1 m spaced 2D GPR profiles.

We have developed a GPR tool which produces interpretable 3D cubes and animations within 1-2 hours after the last trace has been acquired. Previously this step took several weeks to complete. The new 3D GPR offers near-instant views inside the rock volume when outcrop exposure is limited and can be used to test geological hypotheses while in the field. Use of 3D GPR will help develop better reservoir models in less time, with fewer but more critical samples, integrating sedimentology, stratigraphy, structure and geochemistry in an accurate 3D spatial framework.

Movies of 3D GPR cubes imaging sedimentary structures and fractures can be viewed at http://mgg.rsmas.miami.edu/groups/csl/gpr/index.htm

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005