Porous media consolidated materials

Magnetic resonance imaging (MRI) has been applied to the study of the distribution of fluid components (i.e., water or a polymer used as consolidant) in a porous material such as stone or waterlogged wood by a direct visualization of the water or fluid confined in the opaque porous medium [13]. 

Porous medium is a material consisting of a solid matrix with interconnected pores. The interconnected pores are responsible for allowing a fluid to traverse through the material. For the simplest situation, the medium is saturated with a single fluid ( single fluid flow ). In multiphase fluid flow, several fluids (liquids and/or gas) share the open pores. Porous media are classified as unconsolidated and consolidated. 

Porous Medium A solid containing voids or pore spaces. Normally such pores are quite small compared with the size of the solid and well-distributed throughout the solid. In geologic formations, porosity may be associated with unconsolidated (uncemented) materials, such as sand, or a consolidated material, such as sandstone. 

The AECL team used an in-house MOTIF finite-element code (Guvanasen and Chan 2000), which is based on an extension of the classical poroelastic theory of Biot (1941). This code has undergone extensive verification and validation (Chan et al. 2003). The CTH team employed the commercially available, general-purpose finite-element code ABAQUS/Standard 6.3 (ABAQUS manuals). This code adopts a macroscopic thermodynamic approach. The porous medium is considered as a multiphase material, and an effective stress principle is used to describe its behaviour. ABAQUS allows the value of bulk modulus of the mineral grains as an input parameter. In order to select an appropriate value for this low-permeability, low-porosity rock, the CTH team compared the ABACjus solution with Biot s (1941) analytical solution for ID consolidation in the form presented by Chan et al. 2003). 

Consolidated porous media here, the contact (cohesive) forces between elementary grains maintain the mechanical stability of the material. Usual examples of consolidated porous media include calcareous rocks, clays, vegetable, and animal tissues. The deformation or mechanical equilibrium of the porous medium is not a concern, unless its mechanical breakdown under the effect of strong forces is considered. 

The term porosity refers to the fraction of the medium that contains the voids. When a fluid is passed over the medium, the fraction of the medium (i.e., the pores) that contributes to the flow is referred to as the effective porosity of the media. In a general sense, porous media are classified as either unconsolidated and consolidated and/or as ordered and random. Examples of unconsolidated media are sand, glass beads, catalyst pellets, column packing materials, soil, gravel and packing such as charcoal. 

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