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Title: SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

Abstract

In fully-saturated rock and at ultrasonic frequencies, the microscopic squirt flow induced between the stiff and soft parts of the pore space by an elastic wave is responsible for velocity-frequency dispersion and attenuation. In the seismic frequency range, it is the macroscopic cross-flow between the stiffer and softer parts of the rock. We use the latter hypothesis to introduce simple approximate equations for velocity-frequency dispersion and attenuation in a fully water saturated reservoir. The equations are based on the assumption that in heterogeneous rock and at a very low frequency, the effective elastic modulus of the fully-saturated rock can be estimated by applying a fluid substitution procedure to the averaged (upscaled) dry frame whose effective porosity is the mean porosity and the effective elastic modulus is the Backus-average (geometric mean) of the individual dry-frame elastic moduli of parts of the rock. At a higher frequency, the effective elastic modulus of the saturated rock is the Backus-average of the individual fully-saturated-rock elastic moduli of parts of the rock. The difference between the effective elastic modulus calculated separately by these two methods determines the velocity-frequency dispersion. The corresponding attenuation is calculated from this dispersion by using (e.g.) the standard linear solid attenuationmore » model.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Rock Solid Images (US)
Sponsoring Org.:
(US)
OSTI Identifier:
834452
DOE Contract Number:  
FC26-01BC15356
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Jul 2002
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; ULTRASONIC WAVES; ATTENUATION; FREQUENCY RANGE; POROSITY; RESERVOIR ROCK; CALCULATION METHODS; WATER SATURATION

Citation Formats

Walls, Joel, Taner, M T, Mavko, Gary, and Dvorkin, Jack. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION. United States: N. p., 2002. Web. doi:10.2172/834452.
Walls, Joel, Taner, M T, Mavko, Gary, & Dvorkin, Jack. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION. United States. https://doi.org/10.2172/834452
Walls, Joel, Taner, M T, Mavko, Gary, and Dvorkin, Jack. Mon . "SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION". United States. https://doi.org/10.2172/834452. https://www.osti.gov/servlets/purl/834452.
@article{osti_834452,
title = {SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION},
author = {Walls, Joel and Taner, M T and Mavko, Gary and Dvorkin, Jack},
abstractNote = {In fully-saturated rock and at ultrasonic frequencies, the microscopic squirt flow induced between the stiff and soft parts of the pore space by an elastic wave is responsible for velocity-frequency dispersion and attenuation. In the seismic frequency range, it is the macroscopic cross-flow between the stiffer and softer parts of the rock. We use the latter hypothesis to introduce simple approximate equations for velocity-frequency dispersion and attenuation in a fully water saturated reservoir. The equations are based on the assumption that in heterogeneous rock and at a very low frequency, the effective elastic modulus of the fully-saturated rock can be estimated by applying a fluid substitution procedure to the averaged (upscaled) dry frame whose effective porosity is the mean porosity and the effective elastic modulus is the Backus-average (geometric mean) of the individual dry-frame elastic moduli of parts of the rock. At a higher frequency, the effective elastic modulus of the saturated rock is the Backus-average of the individual fully-saturated-rock elastic moduli of parts of the rock. The difference between the effective elastic modulus calculated separately by these two methods determines the velocity-frequency dispersion. The corresponding attenuation is calculated from this dispersion by using (e.g.) the standard linear solid attenuation model.},
doi = {10.2172/834452},
url = {https://www.osti.gov/biblio/834452}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {7}
}