Reflection and transmission coefficients of a single layer in poroelastic media

Wave propagation in poroelastic media is a subject that finds applications in many fields of research, from geophysics of the solid Earth to material science. In geophysics, seismic methods are based on the reflection and transmission of waves at interfaces or layers. It is a relevant canonical problem, which has not been solved in explicit form, i.e., the wave response of a single layer, involving three dissimilar media, where the properties of the media are described by Biot's theory. The displacement fields are recast in terms of potentials and the boundary conditions at the two interfaces impose continuity of the solid and fluid displacements, normal and shear stresses, and fluid pressure. The existence of critical angles is discussed. The results are verified by taking proper limits—zero and 100% porosity—by comparison to the canonical solutions corresponding to single-phase solid (elastic) media and fluid media, respectively, and the case where the layer thickness is zero, representing an interface separating two poroelastic half-spaces. As examples, it was calculated the reflection and transmission coefficients for plane wave incident at a highly permeable and compliant fluid-saturated porous layer, and the case where the media are saturated with the same fluid.Facultad de IngenieríaFacultad de Ciencias Astronómicas y Geofísica

Reflection and transmission coefficients of a single layer in poroelastic media

Wave propagation in poroelastic media is a subject that finds applications in many fields of research, from geophysics of the solid Earth to material science. In geophysics, seismic methods are based on the reflection and transmission of waves at interfaces or layers. It is a relevant canonical problem, which has not been solved in explicit form, i.e., the wave response of a single layer, involving three dissimilar media, where the properties of the media are described by Biot's theory. The displacement fields are recast in terms of potentials and the boundary conditions at the two interfaces impose continuity of the solid and fluid displacements, normal and shear stresses, and fluid pressure. The existence of critical angles is discussed. The results are verified by taking proper limits—zero and 100% porosity—by comparison to the canonical solutions corresponding to single-phase solid (elastic) media and fluid media, respectively, and the case where the layer thickness is zero, representing an interface separating two poroelastic half-spaces. As examples, it was calculated the reflection and transmission coefficients for plane wave incident at a highly permeable and compliant fluid-saturated porous layer, and the case where the media are saturated with the same fluid.Facultad de IngenieríaFacultad de Ciencias Astronómicas y Geofísica

Numerical simulation in Applied Geophysics : From the mesoscale to the macroscale

This paper presents a collection of finite element procedures to model seismic wave propagation at the macroscale taking into account the effects caused by heterogeneities occuring at the mesoscale. For this purpose we first apply a set of compressibility and shear experiments to representative samples of the heterogeneous fluid saturated material. In turn these experiments yield the effective coefficients of an anisotropic macroscopic medium employed for numerical simulations at the macroscale. Numerical experiments illustrate the implementation of the proposed methodology to model wave propagation at the macroscale in a patchy brine-CO2 saturated porous medium containing a dense set of parallel fractures.Facultad de Informátic

Análisis de la calidad de la imagen sísmica en atributos 3D, al aplicar una nueva definición de binning en la migración Kirchhoff pre-apilado

Este proyecto aborda dos técnicas de migración, aplicadas en el procesamiento de datos sísmicos. Dichas metodologías se basan en la migración Kirchhoff pre- apilado y se diferencian en la definición geométrica del binning por acimut. Una es la definición formal, en la cual solo se tiene en cuenta la posición fuente-receptor, y la otra que se basa en una nueva definición de acimut, en la cual se tiene en cuenta la posición fuente-punto imagen y receptor punto imagen.xiv. 112 p.Contenido parcial: Esquema sencillo de reflexión de rayos -- Esquema básico de la migración Kirchhoff 2D -- Diagrama de la geometría usada en la migración Kirchhoff 3D -- Grilla de ángulos usada para la migración -- Columna estratigráfica de la zona de estudio