Computation of Wave Attenuation and Dispersion, by Using Quasi-Static Finite Difference Modeling Method in Frequency Domain

Adnan Ahmad Qazi, Guochen Wu, Wu Jianlu

Abstract


In seismology, seismic numerical modeling is regarded as a useful tool to interpret seismic responses. The presence of subsurface heterogeneities at various scales can lead to attenuation and dispersion during seismic wave propagation. In ongoing global research, the study of wave attenuation and velocity dispersion due to wave induced fluid flow (WIFF) at mesoscopic scale become the subject of great interest. Although, seismic modeling technique is efficient in estimating wave attenuation and velocity dispersion due to wave induced fluid flow (WIFF) at mesoscopic scale.  It is possible to further improve the efficiency to accurately predict wave attenuation and velocity dispersion at mesoscopic scale. To achieve this goal, a quasi-static finite difference modeling method in frequency domain is implemented to estimate frequency dependent P-wave modulus of mesoscopic heterogeneous porous media. The estimated complex and frequency dependent P-wave modulus will assist to estimate frequency dependent wave attenuation and velocity dispersion within a saturated porous media exhibiting mesoscopic heterogeneities. The proposed quasi-static finite difference modeling method is further validated with theoretically predicted high and low-frequency limits and also with the analytical solution of White’s 1-D model which is for rock saturated with two immiscible fluids creating heterogeneity at mesoscopic scale. Furthermore, the proposed method is further extended to rock saturated with three phase fluids exhibiting heterogeneity at mesoscopic scale. Subsequently, seismic wave attenuation (inverse quality factor Q-1) and the effects on P-wave velocity in 1-D models with different patch size under same gas saturation were also computed. Our proposed quasi-static method is simple to be implemented by the computing scheme of parallelization and have a potential to extend it for two-dimensional case comparatively in a flexible way.

Keywords


Interpretation, Seismic waves, Incompressibility, Attenuation, Poroelastic

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References


DOI: http://dx.doi.org/10.4401/ag-7450


 

Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN:  2037-416X