Multiscale Characterization of Geological Properties of Oil Shale

Abstract:

Detailed characterization of geologic properties of oil shale is important for predictive modeling of geomechanics as well as heat and mass transfer in these geomaterials. Specifically, quantitative knowledge of the spatial distribution of thermal, hydraulic, and mechanical properties is requisite. The primary parameter upon which these properties strongly depend is kerogen content. We have developed a simple but accurate method for quantifying the spatial distribution of kerogen content, spanning scales from a few microns to a hundred feet. Our approach is based on analyzing raw optical images. Promising results regarding the viability of this approach, based on comparison with lab measurements, are presented for the well-known Mahogany Zone of the Green River Formation, Utah. A combination of Scanning Electron Microscopy (SEM) and appropriately chosen mixing rules allows for the quantification of thermal, hydraulic, and mechanical properties with micron-scale resolution. Numerical upscaling can subsequently produce averaged properties at the scale of individual grid blocks in field-scale simulators.