In:
GEOPHYSICS, Society of Exploration Geophysicists
Abstract:
In a viscoacoustic medium, intrinsic attenuation causes seismic wavefields to attenuate in amplitude and become dispersed in phase, leading to distorted structural imaging and inaccurate migrated amplitudes. To address this problem, viscoacoustic RTMs correct for dispersion and amplitude attenuation effects in wavefield propagation in both forward and backward directions. To provide a parallel alternative approach, we solve the time fractional derivative viscoacoustic wave equation within the depth domain and establish a Q-compensated wavefield depth extrapolation scheme to compensate for viscoacoustic effects during recursive wavefield depth extrapolation. This approach decouples the amplitude attenuation and phase dispersion effects from the viscoacoustic vertical wavenumber. To suppress high wavenumber components and address the problem of amplitude exponential growth during wavefield depth extrapolation, we limit the imaginary part of the vertical wavenumber in the frequency wavenumber domain and employ an adaptive stabilization solution. Numerical experiments of impulse responses in an isotropic medium demonstrate that our proposed scheme can observe wavefields with amplitude attenuation and phase dispersion effects in comparison to wavefields of the acoustic medium. We also demonstrate the capability of our proposed scheme in recovering imaging amplitudes through a variety of numerical experiments, including imaging of three-layer, Marmousi, and BP gas reservoir models. The results show that our proposed scheme can recover amplitude attenuation and phase dispersion effects correctly compared with the results of acoustic migration. We also use marine seismic data featuring natural gas hydrates to show that our proposed Q-compensated scheme can generate an enhanced imaging result, especially for the bottom simulating reflectors (BSRs), compared with the conventional imaging algorithm without considering Q-compensation.
Type of Medium:
Online Resource
ISSN:
0016-8033
,
1942-2156
DOI:
10.1190/geo2022-0542.1
Language:
English
Publisher:
Society of Exploration Geophysicists
Publication Date:
2023
detail.hit.zdb_id:
2033021-2
detail.hit.zdb_id:
2184-2
SSG:
16,13
