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The Composite Azimuthal Effect of Intrinsic and Scattering Attenuation on 3D Seismic Data
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
The seismic attenuation we observed from previous studies at various sites suggested the complexity of imaging in a hardrock environment. Firstly, the attenuation effect is extremely strong from VSP measurements. It causes the loss of unconformity images along distinct sections. Secondly, the strong attenuation is highly localized. Observation from the surface 3D seismic datasets indicated that the low Q structures occur vertically with specific elongated shapes. We conduct a 3D full waveform Finite-Difference (FD) viscoelastic modelling to illustrate this type of complexity. The 3D model consists of vertical low-Q-low-Vp and high-Q-high-Vp zones. Thus, both of the intrinsic and scattering attenuation effects are embedded. The result implies the surface observed seismic amplitude can exhibit azimuthal variations under the influence of both of these two effects. The local amplitude fast decaying direction may not align with the true low Q or high velocity directions.