Effect of Microgeometry on Modeling Accuracy of Fluid-Saturated Rock Using Dielectric Permittivity

A common practice for estimating subsurface constituents from remote sensing methods is to use analytical effective medium models relating effective dielectric permittivity to properties of the targeted region. These models suggest that the effective permittivity depends on the volumetric fraction and phase property of each constituent of the composite. Most effective medium models are based on idealized approximations of the composite's geometry. Some studies have shown that the analytical mixing rule may underestimate or overestimate the effective property when there are geometrical variations. In this paper, we use numerical experiments to compute the effective dielectric permittivity of composites with different microgeometries having varying amounts of internal interfaces. By comparing the numerical results with the classic analytical mixing rules, we quantify the discrepancy with a diagram that indicates the high deviation region. The study is carried out by using various fluid-solid permittivity contrasts to suit a wide range of applications.