Wave attenuation across a thin reservoir mainly includes intrinsic attenuation and scattering attenuation.The former is caused by the viscoelasticity of media within seismic frequency band,and the latter manifests as tuning effect in a thin layer.In or-der to clarify the influence of reservoir thickness on seismic waves,we use the generalized propagation matrix to perform forward modeling of amplitude variation with offset for an isotropic and an anisotropic wedge model,and then extract the dispersion attrib-ute from modelled data using a modified inversion spectral decomposition and frequency-dependent AVO inversion to investigate the impact of reservoir thickness on seismic-wave dispersion.The results indicate that intrinsic attenuation significantly reduces the reflection amplitude from the reservoir,while scattering attenuation causes reflection amplitude to first increase and then decrease with thickness.Seismic-wave dispersion shows a M-shaped curve as reservoir thickness increases,on which two maxima appear at the thicknesses around 1/20 wavelength and 1/2 wavelength,respectively,and the minimum at 1/4 wavelength.When reservoir thickness is less than 1/4 wavelength,scattering attenuation shows a stronger influence on reflection amplitude and dispersion than intrinsic attenuation.
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