Potential of Seismic Attenuation for Exploring Complex Media: A Focus on Carbonate Rocks

Considerable effort has been dedicated to the potential of seismic attenuation for investigating complex media, such as fractured reservoir zones. Several seismic attenuation studies have been conducted on carbonate rocks, but far fewer than in sandstones.Gray zonesmay be explained by the complex lithology and intricate porous network, which makes carbonatemedia particularly challenging to analyze in terms of seismic attenuation.Nevertheless, significant efforts have been devoted to shedding light on the sensitivity of seismic attenuation to petrophysical properties and its mechanism in carbonate rocks. The notable difference between sandstones and carbonate rocks was observed in the compressional to shear attenuation ratio Q_P^-1/Q_S^-1 and scattering magnitudes. In fully saturated media, Q_P^-1/Q_S^-1 exhibits magnitudes higher than one, whereas in partially saturated media, it exhibits magnitudes lower than one, contrary to siliciclastic media. It is worth noting that in carbonate rocks, the scattering mechanism is more significant than in siliciclastic media, where it is often considered insignificant. The squirt flow mechanism becomes more prominent at sonic frequencies, whereas global flow and frictional sliding may dominate at other frequencies. This highlights the complexity and frequency-dependent nature of attenuation mechanisms in carbonate rocks.