Heterogeneity and Scaling in Geologic Media: Applications to Transport in the Vadose and Saturated Zones

Technical Report · Tue Dec 13 04:00:00 EST 2005

OSTI ID:861363

Brown, Stephen R ^[1]; Boitnott, Gregory; Bussod, Gilles Y; Hagin, Paul

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1. New England Research

In building models of the subsurface, it is generally acknowledged that the required properties are rarely known or observed at the scale of the model elements. Typically they are constrained by measurements or observations made at other scales such as smaller scale core measurements or larger scale wellbore or field tests. As a result, model parameters contain a certain level of uncertainty even in the best of cases. These values typically require adjustment to fit field observations through a process commonly referred to as calibration. The characterization of flow and transport in the vadose and saturated zones, requires a detailed knowledge of subsurface structures, flow paths, and hydrophysical properties. We have constructed a methodology and workflow that use fine-scale measurements of heterogeneity to constrain physically based models for upscaling geophysical and hydrological properties. The methodology provides a means to assign hydrophysical properties at scales more appropriate to field applications, while preserving a physical influence of fine scale heterogeneities. We start by describing millimeter-scale physical properties measurements made on the surface of a sample. Combining physical properties maps and measured parameters with effective medium models, we show that these fine-scale heterogeneities can cause saturation dependent anisotropy in several properties such as electrical conductivity, relative permeability and velocity. Finally, we demonstrate that traditional upscaling of multiphase properties such as capillary pressure leads to inaccuracies that can be avoided by employing upscaling that explicitly incorporates fine-scale heterogeneity. This methodology provides a more accurate interpretation and representation of the subsurface for both environmental and fossil fuel reservoir applications, and can be extended to the study of surface damage in man made structures such as concrete. Realistic hydrologic, geophysical and hydrochemical parameters linked to mesoscale heterogeneities obtained from this method are the foundation for physically based upscaling through the use of physical constitutive relationships, properly calibrated mathematical models and geostatistical analyses.

• Research Organization: New England Research, 331 Olcott Drive Ste L1, White River Junction, VT 05001
• Sponsoring Organization: USDOE - Office of Environmental Management (EM)
• DOE Contract Number: FG07-02ER63497
• OSTI ID: 861363
• Report Number(s): DOE-ER63497-NER-FR01
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
flow and transport
hydrogeology
vadose zone
saturated zone
heterogeneity
scaling
geophysical properties