Attenuation of Coda Waves in the Central Alborz, Iran

Traditionally, estimates of inverse quality factor Q-1 as a measure of intrinsic attenuation are extracted from the wavelet w(t) amplitude spectrum assuming preferential absorption of high frequency component of the spectrum. In contrast, the energy losses associated with reflections from interfaces between layers with different absorption were considered by now mainly theoretically. We show that time windows implemented in these two techniques shall be localized differently. Also, we present a new set of frequency-dependent attributes to be used in predicting storage capacity, permeability, and oil production rate from seismic reflections originated within the reservoir. At a series of oil fields, the increase of porosity, permeability and production rate correlates with the increase of relative energy of high frequencies. At several other oil fields, the reverse trend is observed. Assumingly, this diversity is caused by the difference in the pore space microgeometry: the increase of high frequency amplitudes with the reservoir properties enhancement is inherent in reservoir rocks with dual porosity and dual permeability.