Integration of GPR, GPS, Remote Sensing and Geochemistry for Shallow Reservoir Studies in Central and South-Central Texas

Damayanti Mukherjee, Shuhab D. Khan, and Charlotte E. Sullivan
University of Houston, Houston, TX

Albian rudist communities of the Edwards Formation, Fredericksburg Group, occur widely in Central and South-Central Texas. Capped by younger dolostones of the Fredericksburg Group, they form important reservoir analogs for highly productive oil-fields in the Middle East. This study covers exposures of Albian rudists and associated sequences in and around Belton (Bell County), Georgetown (Williamson County), Austin (Travis County), Fredericksburg (Gillespie County) and Kerrville (Kerr County) in Central and South-Central Texas.

Ground Penetrating Radar (GPR) technology aided by Hyperion hyperspectral remote sensing and field spectroscopy data are being used to determine the 3-D facies geometry and facies heterogeneity as part of a larger project. For this work, we are using 100 and 400 MHz antennae with the Subsurface Interface Radar (SIR-3000) System by GSSI. The Hyperion hyperspectral imager is capable of resolving 220 spectral bands with a 30 meter spatial resolution, allowing us to image and classify complex sequences. GPR data is providing better knowledge of the 3-D architecture and extent of the rudist mounds. GPS and GPR data are being tied together for more accurate geographic positioning. Future work will involve use of isotope geochemistry of these sequences to correlate units between the different outcrops, to demarcate the major sequence boundaries and to look into sea-level fluctuations during Albian times. Trace element chemistry of the carbonates will be used to unravel the paleoclimatic signature in the sequences. Integration of the various datasets will eventually provide a comprehensive character of the reservoir geometry, facies changes, the associated paleoenvironment and paleoclimate.