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The Effect of Frequency-dependent Reflection Coefficient on Seismic Attenuation Estimation
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
Seismic attenuation can be quantified by quality factor Q. Accurate estimation of Q factor is of great significance in exploration geophysics. Currently, most Q estimation methods are based on plane wave theory and assume that the reflection effect is frequency-independent. In fact, real seismic surveys use localized sources which produce spherical waves rather than plane waves. Thus spherical wave theory can give more precise description of real seismic reflection than plane wave theory. However, spherical wave reflectivity (SWR) is frequency-dependent and the frequency-dependent effect is often neglected. In this paper, we use a two-layer model to illustrate the influence of the frequency-dependence of SWR on seismic attenuation estimation. Tests show that the amplitude spectrum of reflection spherical wave has an obvious frequency shift to low frequency compared with the original wavelet spectrum. The estimated Q value is smaller than the real one due to the frequency-dependent effect of SWR. Thus it is important to consider the influence of frequency-dependent SWR on Q estimation in order to accurately estimate and compensate for attenuation.