Numerical simulation of wave-induced fluid flow seismic attenuation based on the Cole-Cole model

Area of Science:

• Geophysics
• Computational Seismology
• Porous Media Physics

Background:

• Realistic simulation of porous media acoustics requires advanced stress-strain relations.
• Mesoscopic-loss models, particularly the Cole-Cole model, accurately describe seismic velocity dispersion and attenuation in rocks.
• The Zener model offers a less accurate approximation for wave propagation simulation.

Purpose of the Study:

• To develop and validate a time-domain algorithm for simulating wave propagation using the Cole-Cole model.
• To apply the developed methodology to model seismic monitoring for CO2 sequestration in saline aquifers.
• To assess the sensitivity of seismic methods for detecting potential CO2 leakage.

Main Methods:

• Implementation of a time-domain algorithm using the Grünwald-Letnikov approximation for fractional derivatives.
• Computation of spatial derivatives via the Fourier pseudospectral method.
• Validation of the numerical solution against an analytical solution.

Main Results:

• The proposed algorithm accurately simulates seismic wave propagation based on the Cole-Cole model.
• The methodology was successfully applied to a saline aquifer model with CO2 injection.
• Simulations demonstrated the potential for detecting gas leakage in partially saturated sandstone.

Conclusions:

• The developed time-domain algorithm provides a realistic and accurate simulation of acoustic behavior in porous media.
• This approach is valuable for seismic monitoring strategies in CO2 sequestration projects.
• The study highlights the importance of assessing seismic method sensitivity for effective leakage detection.