# 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 »

- 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}

}