Characterization of fluvial reservoir analogs by modeling and inversion of petrophysical and electrical properties

Ground-penetrating radar (GPR) has found increasing application in the past several years as a high frequency electromagnetic tool for providing high-resolution imaging of the earth's near-surface geologic environment.; Two 3-D GPR data volumes were acquired in the Ferron sandstone of east-central Utah to test the feasibilty of using 3-D GPR for stratigraphic and structural imaging of the near-surface. Integration of 3-D GPR radar surveys with sedimentological and stratigraphic data provides information on the internal heterogeneities of sedimentary sequences. The data show features that match well with adjacent cliff faces.; A three-dimensional (3-D) 100 MHz GPR data volume is the basis of in-situ characterization of a fluvial reservoir analog.; As part of the 3-D characterization of a fluvial reservoir analog site in the Ferron Sandstone new lab measurements of porosity, permeability, water content, and complex dielectric permittivity are collected and analyzed. Petrographic analysis of thin sections extracted from the same samples produced data on bulk, macro- and micro-porosity, lithology, and cementation. Variations in clay fraction, permeability, porosity, and/or water content may be predicted from measurable electrical properties.; The permittivities vary systematically and are approximately predicted by effective medium models. It is concluded that the reliability of the estimated water content is much better than that of the estimated water permittivity at low saturation levels.; The complex dielectric permittivity of a material is the essential parameter which controls its GPR response. The permittivity due to a dilute dipole concentration assumption of the Maxwell-Garnett (M-G) theory and from the differential effective medium (DEM) theory are compared with a finite-element (FE) implementation of multipole theory. Porous medium models of sedimentary rocks are built with the GCM theory. Predictions of the permittivity in a homogeneous and isotropic porous medium for the M-G model and the FE model show that the M-G model is inadequate for modeling multipole polarization. The permittivity predictions for the DEM model and the FE model are very similar. (Abstract shortened by UMI.)...