TY - JOUR

T1 - Modeling Frequency-Independent Q Viscoacoustic Wave Propagation in Heterogeneous Media

AU - Xing, Guangchi

AU - Zhu, Tieyuan

N1 - Funding Information:
This work was supported by the National Energy Technology Laboratory of the U.S. Department of Energy, under the U.S. DOE Contract DE‐FE0031544 and the NSF Grant EAR 1919650. All data can be freely accessed on the Energy Data eXchange (EDX, https://edx.netl.doe.gov/dataset/frio-2-raw-cassm-datasets ), operated by the National Energy Technology Laboratory and utilized under the terms of the Creative Commons Attribution (CCA) license.
Funding Information:
This work was supported by the National Energy Technology Laboratory of the U.S. Department of Energy, under the U.S. DOE Contract DE-FE0031544 and the NSF Grant EAR 1919650. All data can be freely accessed on the Energy Data eXchange (EDX, https://edx.netl.doe.gov/dataset/frio-2-raw-cassm-datasets), operated by the National Energy Technology Laboratory and utilized under the terms of the Creative Commons Attribution (CCA) license.

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Quantifying the attenuation of seismic waves propagating in the Earth interior is critical to study the subsurface structure. Previous studies have proposed fractional anelastic wave equations to model the frequency-independent Q seismic wave propagation. Such wave equations involve fractional derivatives that pose computational challenges for the numerical schemes in terms of accuracy and efficiency when dealing with heterogeneous Earth media. To tackle these challenges, here we derive a new viscoacoustic wave equation, where the power terms of the fractional Laplacian operators are spatially independent, thus accurate and efficient methods (e.g., the Fourier pseudospectral method) can be adopted. Our derivation enables the resultant equation to capture both amplitude and phase signatures of the anelastic wave propagation by matching the complex wave numbers for all the frequencies of interest. We verify the derivation by comparing the dispersion curves of both the attenuation factor and the phase velocity produced by the new wave equation with their theoretical values as well as the Pierre Shale in situ measurements. Following that, we use a synthetic attenuating gas chimney model to demonstrate the attenuation effects on seismic waveforms and then construct the Q-compensated reverse time migration to undo these effects for seismic image enhancement. Finally, we find that our forward modeling results can characterize the spatiotemporal attenuation effects revealed in the Frio-II CO2 injection time-lapse seismic monitoring data. We expect this proposed equation to be useful to quantify the attenuation in seismic data to push the resolution limits of seismic imaging and inversion.

AB - Quantifying the attenuation of seismic waves propagating in the Earth interior is critical to study the subsurface structure. Previous studies have proposed fractional anelastic wave equations to model the frequency-independent Q seismic wave propagation. Such wave equations involve fractional derivatives that pose computational challenges for the numerical schemes in terms of accuracy and efficiency when dealing with heterogeneous Earth media. To tackle these challenges, here we derive a new viscoacoustic wave equation, where the power terms of the fractional Laplacian operators are spatially independent, thus accurate and efficient methods (e.g., the Fourier pseudospectral method) can be adopted. Our derivation enables the resultant equation to capture both amplitude and phase signatures of the anelastic wave propagation by matching the complex wave numbers for all the frequencies of interest. We verify the derivation by comparing the dispersion curves of both the attenuation factor and the phase velocity produced by the new wave equation with their theoretical values as well as the Pierre Shale in situ measurements. Following that, we use a synthetic attenuating gas chimney model to demonstrate the attenuation effects on seismic waveforms and then construct the Q-compensated reverse time migration to undo these effects for seismic image enhancement. Finally, we find that our forward modeling results can characterize the spatiotemporal attenuation effects revealed in the Frio-II CO2 injection time-lapse seismic monitoring data. We expect this proposed equation to be useful to quantify the attenuation in seismic data to push the resolution limits of seismic imaging and inversion.

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U2 - 10.1029/2019JB017985

DO - 10.1029/2019JB017985

M3 - Article

AN - SCOPUS:85075028671

VL - 124

SP - 11568

EP - 11584

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 11

ER -