Viscosity scaling of wave attenuation mechanisms in porous rocks: Theory and numerical simulations

2011 ◽  
Author(s):  
Tobias M. Müller ◽  
Erik H. Saenger ◽  
Pratap N. Sahay
Keyword(s):  
Numerical Simulations ◽  
Wave Attenuation ◽  
Porous Rocks

scholarly journals Probing of molecular replication and accumulation in shallow heat gradients through numerical simulations

2016 ◽  
Vol 18 (30) ◽  
pp. 20153-20159 ◽  
Author(s):  
Lorenz Keil ◽  
Michael Hartmann ◽  
Simon Lanzmich ◽  
Dieter Braun
Keyword(s):  
Numerical Simulations ◽  
Temperature Gradients ◽  
Porous Rocks ◽  
Highly Efficient ◽  
Temperature Oscillations ◽  
Molecular Replication

Shallow temperature gradients across porous rocks drive highly efficient molecular accumulation processes while simultaneously subjecting them to frequent temperature oscillations.

Anisotropic P-SV-wave dispersion and attenuation due to inter-layer flow in thinly layered porous rocks

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. WA135-WA145 ◽  
Author(s):  
Fabian Krzikalla ◽  
Tobias M. Müller
Keyword(s):  
Wave Attenuation ◽  
Fluid Pressure ◽  
Pore Fluid ◽  
P Wave ◽  
Angle Of Incidence ◽  
Porous Rocks ◽  
Frequency Dependent ◽  
Symmetry Properties ◽  
Wave Induced ◽  
Attenuation And Dispersion

Elastic upscaling of thinly layered rocks typically is performed using the established Backus averaging technique. Its poroelastic extension applies to thinly layered fluid-saturated porous rocks and enables the use of anisotropic effective medium models that are valid in the low- and high-frequency limits for relaxed and unrelaxed pore-fluid pressures, respectively. At intermediate frequencies, wave-induced interlayer flow causes attenuation and dispersion beyond that described by Biot’s global flow and microscopic squirt flow. Several models quantify frequency-dependent, normal-incidence P-wave propagation in layered poroelastic media but yield no prediction for arbitrary angles of incidence, or for S-wave-induced interlayer flow. It is shown that generalized models for P-SV-wave attenuation and dispersion as a result of interlayer flow can be constructed by unifying the anisotropic Backus limits with existing P-wave frequency-dependent interlayer flow models. The construction principle is exact and is based on the symmetry properties of the effective elastic relaxation tensor governing the pore-fluid pressure diffusion. These new theories quantify anisotropic P- and SV-wave attenuation and velocity dispersion. The maximum SV-wave attenuation is of the same order of magnitude as the maximum P-wave attenuation and occurs prominently around an angle of incidence of [Formula: see text]. For the particular case of a periodically layered medium, the theoretical predictions are confirmed through numerical simulations.

Experimental evidence for the Biot‐Gardner theory

Geophysics ◽  
1989 ◽  
Vol 54 (4) ◽  
pp. 524-527 ◽  
Author(s):  
R. Mörig ◽  
H. Burkhardt
Keyword(s):  
Experimental Evidence ◽  
Seismic Wave ◽  
Seismic Data ◽  
Seismic Waves ◽  
Wave Attenuation ◽  
Wide Spectrum ◽  
Seismic Energy ◽  
Porous Rocks ◽  
Saturation State ◽  
Seismic Wave Attenuation

Seismic wave attenuation has been a subject of interest during the last 40 years because it may be of use in interpreting seismic data. From this attenuation parameter, more detailed information about the lithology of the subsurface may be deduced if we understand the absorption mechanisms by which dissipation of seismic energy is governed. We are, therefore, studying in the laboratory the effects of different parameters such as porosity, permeability, pore fluid, and saturation state on the absorption of seismic waves in porous rocks over a wide spectrum ranging from seismic to ultrasonic frequencies (Burkhardt et al., 1986).

Generalization of Gassmann equations for porous media saturated with a solid material

Geophysics ◽  
2007 ◽  
Vol 72 (6) ◽  
pp. A75-A79 ◽  
Author(s):  
Radim Ciz ◽  
Serge A. Shapiro
Keyword(s):  
Numerical Simulations ◽  
Elastic Properties ◽  
Pore Space ◽  
Viscoelastic Model ◽  
Solid Material ◽  
Filling Material ◽  
Porous Rocks ◽  
Pore Filling ◽  
Effective Elastic Properties ◽  
New Model

Gassmann equations predict effective elastic properties of an isotropic homogeneous bulk rock frame filled with a fluid. This theory has been generalized for an anisotropic porous frame by Brown and Korringa’s equations. Here, we develop a new model for effective elastic properties of porous rocks — a generalization of Brown and Korringa’s and Gassmann equations for a solid infill of the pore space. We derive the elastic tensor of a solid-saturated porous rock considering small deformations of the rock skeleton and the pore infill material upon loading them with the confining and pore-space stresses. In the case of isotropic material, the solution reduces to two generalized Gassmann equations for the bulk and shear moduli. The applicability of the new model is tested by independent numerical simulations performed on the microscale by finite-difference and finite-element methods. The results show very good agreement between the new theory and the numerical simulations. The generalized Gass-mann model introduces a new heuristic parameter, characterizing the elastic properties of average deformation of the pore-filling solid material. In many cases, these elastic moduli can be substituted by the elastic parameters of the infill grain material. They can also represent a proper viscoelastic model of the pore-filling material. Knowledge of the effective elastic properties for such a situation is required, for example, when predicting seismic velocities in some heavy oil reservoirs, where a highly viscous material fills the pores. The classical Gassmann fluid substitution is inapplicable for a configuration in which the fluid behaves as a quasi-solid.

scholarly journals Dynamic seismic signatures of saturated porous rocks containing two orthogonal sets of fractures: theory versus numerical simulations

2018 ◽  
Vol 213 (2) ◽  
pp. 1244-1262 ◽  
Author(s):  
Junxin Guo ◽  
J Germán Rubino ◽  
Stanislav Glubokovskikh ◽  
Boris Gurevich
Keyword(s):  
Numerical Simulations ◽  
Porous Rocks ◽  
Theory Versus
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