CONNECTION OF ELASTIC AND TRANSPORT PROPERTIES: EFFECTIVE MEDIUM STUDY IN ANISOTROPIC POROUS MEDIA

Date

2013-05

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Abstract

The elastic property of a porous medium is closely related to the elastic properties of all the components, such as stiffness, density, orientation distribution, and the microstructure properties, such as porosity, pore shape, and pore connection. On the other hand, the permeability doesn’t feel the properties of solid matrix and is closely related to the transport properties of the pore fluid and microstructure properties. Therefore, the permeability can be correlated to the elastic properties when we neglect the effect from the matrix. A first attempt has been made to investigate the different influence from microstructure to the elastic property and permeability, using General Singular Approximation (GSA) effective medium theory. The GSA method takes into account the pore connection of the microstructure in porous media by the friability parameter. In this dissertation, first the microstructure properties of Barnett shale have been obtained by GSA inversion; second a GSA-based fluid substitution method has been introduced. The results are given for different pore connection and compared with Gassmann substitution; third and the most important, the GSA method has been used to model both the effective stiffness and effective permeability for the same model at the same time. Thus a series of GSA modeling has been done for the full range of friability and porosity in isotropic and anisotropic models, as a result, three categories of the correlations have been discovered: (1) the correlation between microstructure properties and the elastic properties, including stiffness tensor, Thomsen parameter, velocities, and Biot’s alpha parameter; (2) the correlation between microstructures properties and the permeability; and (3) the correlation between the permeability and the elastic properties, which shows nearly linear relation in the direction parallel to cracks, and hyperbolic relation in the direction vertical to cracks.

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Keywords

EMT, GSA, Microstructure, Pore connectivity, Elasticity, Permeability

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