Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media
Wave-induced fluid flow generates a dominant attenuation mechanism in porous media. It consists of energy loss due to P-wave conversion to Biot (diffusive) modes at mesoscopic-scale inhomogeneities. Fractured poroelastic media show significant attenuation and velocity dispersion due to this mechanis...
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| Autores principales: | , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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2013
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/123607 |
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I19-R120-10915-123607 |
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dspace |
| institution |
Universidad Nacional de La Plata |
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I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Exactas Física fractures anisotropy attenuation boundary conditions |
| spellingShingle |
Ciencias Exactas Física fractures anisotropy attenuation boundary conditions Carcione, José M. Gurevich, Boris Santos, Juan Enrique Picotti, Stefano Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media |
| topic_facet |
Ciencias Exactas Física fractures anisotropy attenuation boundary conditions |
| description |
Wave-induced fluid flow generates a dominant attenuation mechanism in porous media. It consists of energy loss due to P-wave conversion to Biot (diffusive) modes at mesoscopic-scale inhomogeneities. Fractured poroelastic media show significant attenuation and velocity dispersion due to this mechanism. The theory has first been developed for the symmetry axis of the equivalent transversely isotropic (TI) medium corresponding to a poroelastic medium containing planar fractures. In this work, we consider the theory for all propagation angles by obtaining the five complex and frequency-dependent stiffnesses of the equivalent TI medium as a function of frequency. We assume that the flow direction is perpendicular to the layering plane and is independent of the loading direction. As a consequence, the behaviour of the medium can be described by a single relaxation function. We first consider the limiting case of an open (highly permeable) fracture of negligible thickness. We then compute the associated wave velocities and quality factors as a function of the propagation direction (phase and ray angles) and frequency. The location of the relaxation peak depends on the distance between fractures (the mesoscopic distance), viscosity, permeability and fractures compliances. The flow induced by wave propagation affects the quasi-shear (qS) wave with levels of attenuation similar to those of the quasi-compressional (qP) wave. On the other hand, a general fracture can be modeled as a sequence of poroelastic layers, where one of the layers is very thin. Modeling fractures of different thickness filled with CO₂ embedded in a background medium saturated with a stiffer fluid also shows considerable attenuation and velocity dispersion. If the fracture and background frames are the same, the equivalent medium is isotropic, but strong wave anisotropy occurs in the case of a frameless and highly permeable fracture material, for instance a suspension of solid particles in the fluid. |
| format |
Articulo Articulo |
| author |
Carcione, José M. Gurevich, Boris Santos, Juan Enrique Picotti, Stefano |
| author_facet |
Carcione, José M. Gurevich, Boris Santos, Juan Enrique Picotti, Stefano |
| author_sort |
Carcione, José M. |
| title |
Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media |
| title_short |
Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media |
| title_full |
Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media |
| title_fullStr |
Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media |
| title_full_unstemmed |
Angular and Frequency-Dependent Wave Velocity and Attenuation in Fractured Porous Media |
| title_sort |
angular and frequency-dependent wave velocity and attenuation in fractured porous media |
| publishDate |
2013 |
| url |
http://sedici.unlp.edu.ar/handle/10915/123607 |
| work_keys_str_mv |
AT carcionejosem angularandfrequencydependentwavevelocityandattenuationinfracturedporousmedia AT gurevichboris angularandfrequencydependentwavevelocityandattenuationinfracturedporousmedia AT santosjuanenrique angularandfrequencydependentwavevelocityandattenuationinfracturedporousmedia AT picottistefano angularandfrequencydependentwavevelocityandattenuationinfracturedporousmedia |
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Repositorios |
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1764820449865236480 |