Effects of Attenuation on Seismic Reflections

Abstract

Seismic reflections at an interface are often regarded as the variation of the acoustic impedance (product of seismic velocity and density) in a media. In fact, they can also be generated due to the difference in absorption of the seismic energy. In this work, we investigate the impacts of attenuation on seismic reflections based on the diffusive-viscous wave equation, which is used to investigate seismic attenuation and frequency-dependent seismic anomalies related to hydrocarbon reservoirs. The results show that the reflections are significantly affected by the diffusive attenuation but they are insensitive to the viscous attenuation in an acoustic dispersive medium. In an elastic dispersive medium, the attenuation parameter in P wave equation has a big impact on both PP and PS reflections, however, the attenuation parameter in S wave equation has little effect on the PP reflection but it strongly affects the PS reflections. Furthermore, the PP and PS reflections in the dispersive medium are dependent on the frequency, and the effect of attenuation on PP and PS reflections at lower frequencies is bigger than those at higher frequencies.