Tube wave attenuation and dispersion in permeable formations

1986 ◽  
Author(s):  
A. N. Norris
Keyword(s):  
Wave Attenuation ◽  
Tube Wave ◽  
Attenuation And Dispersion

Seismic wave attenuation due to fluid pressure diffusion at the mesoscopic scale: an experimental and numerical study

2021 ◽  
Author(s):  
Samuel Chapman ◽  
Jan V. M. Borgomano ◽  
Beatriz Quintal ◽  
Sally M. Benson ◽  
Jerome Fortin
Keyword(s):  
Seismic Wave ◽  
Seismic Waves ◽  
Wave Attenuation ◽  
Fluid Pressure ◽  
Fluid Distribution ◽  
Mesoscopic Scale ◽  
Seismic Wave Attenuation ◽  
X Ray ◽  
Pressure Diffusion ◽  
Attenuation And Dispersion

<p>Monitoring of the subsurface with seismic methods can be improved by better understanding the attenuation of seismic waves due to fluid pressure diffusion (FPD). In porous rocks saturated with multiple fluid phases the attenuation of seismic waves by FPD is sensitive to the mesoscopic scale distribution of the respective fluids. The relationship between fluid distribution and seismic wave attenuation could be used, for example, to assess the effectiveness of residual trapping of carbon dioxide (CO2) in the subsurface. Determining such relationships requires validating models of FPD with accurate laboratory measurements of seismic wave attenuation and modulus dispersion over a broad frequency range, and, in addition, characterising the fluid distribution during experiments. To address this challenge, experiments were performed on a Berea sandstone sample in which the exsolution of CO2 from water in the pore space of the sample was induced by a reduction in pore pressure. The fluid distribution was determined with X-ray computed tomography (CT) in a first set of experiments. The CO2 exosolved predominantly near the outlet, resulting in a heterogeneous fluid distribution along the sample length. In a second set of experiments, at similar pressure and temperature conditions, the forced oscillation method was used to measure the attenuation and modulus dispersion in the partially saturated sample over a broad frequency range (0.1 - 1000 Hz). Significant P-wave attenuation and dispersion was observed, while S-wave attenuation and dispersion were negligible. These observations suggest that the dominant mechanism of attenuation and dispersion was FPD. The attenuation and dispersion by FPD was subsequently modelled by solving Biot’s quasi-static equations of poroelasticity with the finite element method. The fluid saturation distribution determined from the X-ray CT was used in combination with a Reuss average to define a single phase effective fluid bulk modulus. The numerical solutions agree well with the attenuation and modulus dispersion measured in the laboratory, supporting the interpretation that attenuation and dispersion was due to FPD occurring in the heterogenous distribution of the coexisting fluids. The numerical simulations have the advantage that the models can easily be improved by including sub-core scale porosity and permeability distributions, which can also be determined using X-ray CT. In the future this could allow for conducting experiments on heterogenous samples.</p>

The influence of mesoscopic flow on the P-wave attenuation and dispersion in a porous media permeated by aligned fractures

2013 ◽  
Vol 57 (3) ◽  
pp. 482-506 ◽  
Author(s):  
Jixin Deng ◽  
Shangxu Wang ◽  
Gengyang Tang ◽  
Jianguo Zhao ◽  
Xiangyang Li
Keyword(s):  
Porous Media ◽  
Wave Attenuation ◽  
P Wave ◽  
Attenuation And Dispersion

scholarly journals A model forP-wave attenuation and dispersion in a porous medium permeated by aligned fractures

2005 ◽  
Vol 163 (1) ◽  
pp. 372-384 ◽  
Author(s):  
Miroslav Brajanovski ◽  
Boris Gurevich ◽  
Michael Schoenberg
Keyword(s):  
Porous Medium ◽  
Wave Attenuation ◽  
Attenuation And Dispersion

Stoneley‐wave attenuation and dispersion in permeable formations

Geophysics ◽  
1989 ◽  
Vol 54 (3) ◽  
pp. 330-341 ◽  
Author(s):  
Andrew N. Norris
Keyword(s):  
Dispersion Relation ◽  
Wave Attenuation ◽  
Low Frequency ◽  
Water Infiltration ◽  
Stoneley Wave ◽  
Biot Theory ◽  
Static Approximation ◽  
Quasi Static Approximation ◽  
Tube Wave ◽  
Dynamic Description

The tube wave, or low‐frequency manifestation of the Stoneley wave, has been modeled previously using the quasi‐static approximation; I extend this method to include the effect of the formation matrix compressibility, which tends to marginally increase the tube‐wave attenuation. Using the Biot theory of poroelasticity, I develop a fully dynamic description of the Stoneley wave. The dispersion relation derived from Biot’s equations reduces in the low‐frequency limit to the quasi‐static dispersion relation. Comparisons of the quasi‐static and dynamic theories for typical sandstones indicate the former to be a good approximation to at least 1 kHz for oil and water infiltration. At higher frequencies, usually between 5 and 20 kHz for the formations considered, a maximum in the Stoneley Q is predicted by the dynamic theory. This phenomenon cannot be explained by the quasi‐static approximation, which predicts a constantly increasing Q with frequency. Instead, the peak in Q may be understood as a transition from dispersion dominated by bore curvature to a higher frequency regime in which the Stoneley wave behaves like a wave on a flat fluid‐porous interface. This hypothesis is supported by analytical and numerical results.

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