Capillary Pressure Analysis in Codell Sandstone
Codell Sandstone is an important resource. While core analysis can accurately measure porosity, permeability, saturation and capillary pressure, image-based rock physics can measure and provide data on two- and three-phase relative permeability. This study developed an integrated Core Analysis Image-Based Rock Physics (CA-IBRP) workflow with a robust method for integrating porosity phases and two different resolutions (FIB-SEM and MicroCT) to obtain representative elementary volume pseudo-properties for use in reservoir modeling. The workflow begins with the identification of representative lithofacies from core/logs. Porosity, permeability, saturation, capillary pressure and effective gas 2-P Kr (Keg) are measured using core analysis. MicroCT is then used to characterize the distribution of the five principal MicroCT-image phases: grains (G), intergranular φ (IGV), large clay (kaolinite) + intercrystalline φ (IX), small mixed-layer clay + microcrystalline φ (MIX), and altered lithics + intragranular φ (ING). IGV, IX, MIX, and ING are then imaged with FIB-SEM at respectively appropriate resolutions and quantified using artificial intelligence-based image analytics.
Clay Bound Microporosity
An example image of a principal property object measured and discussed in this paper.
Application of integrated core and multiscale 3D image rock physics to characterize porosity, permeability, capillary pressure, and two- and three-phase relative permeability in the Codell Sandstone, Denver Basin, Colorado
Unconventional Resources Technology Conference paper in collaboration with Whiting