HR: 14:40h
AN: H43J-05    [Abstracts]
TI: Structural - entropic characterization of porous media and systematic derivation of flow properties
AU: * Blumenfeld, R
EM: rbb11@cam.ac.uk
AF: Department of Earth Sciences and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
AU: Frenkel, G
AF: Department of Earth Sciences and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
AU: King, P
AF: Department of Earth Sciences and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
AU: Blunt, M
AF: Department of Earth Sciences and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
AB: A new systematic approach is described for the characterization of porous media and the application of the characterization to derivation and analysis of transport and mechanical properties. The strategy is as follows. 1. The connectivity of the structure is defined. In granular systems it is based on the inter-granular contact network and in cellular solids on the skeleton. The connectivity is characterized by a new fabric tensor. This description makes it possible to quantify structural parameters, such as skeletal pores and throats. 2. An entropic description of the structure is formulated, for which the fabric tensor provides a volume function. This function is the analogue of a Hamiltonian in conventional statistical mechanics. The fundamental 'quasi- particles' in this formalism are not grains or pores, but rather smaller basic volume elements, named quadrons. In systems of N grains and mean grain coordination number z, there are zN quadrons in 2D and 6(z-2)N in 3D. 3. The entropic formalism is used to extract the distribution of the throat size as expectation values over the partition function. 4. The distributions of throat sizes and pore coordination numbers are used to extract an equivalent network of the same structural characteristics as the original porous material. 5. Using existing techniques, it is then possible to compute both the permeability of the equivalent network to flow (of one or more phases) and its electrical conductivity when saturated with brine water. The commonality of these properties as expectation values over the partition function makes it possible to derive first-principles conductivity- permeability relations. The advantages of this strategy are discussed, as well as the difficulties involved in each stage and our progress in the implementation of the programme.
DE: 1816 Estimation and forecasting
DE: 1832 Groundwater transport
DE: 1835 Hydrogeophysics
DE: 1847 Modeling
DE: 3299 General or miscellaneous
SC: Hydrology [H]
MN: 2007 Fall Meeting