Attenuation and velocity dispersion at seismic frequencies

Attenuation and velocity dispersion are strongly dependent on pore fluids, particularly partial gas saturation, and thus could become valuable direct hydrocarbon indicators. Unfortunately, application of these properties is not frequent due to incomplete understanding of the phenomena and lack of appropriate tools to extract the information. Laboratory measurements at frequencies and amplitudes encompassing the seismic range have the strong dependence on partial gas saturation. However, attenuation is decreased by confining pressure, dropping rapidly as pressure increases. Attenuation peaks will also depend on specific rock characteristics. Absorption peaks seen in one frequency band may not be apparent in others.