Recognition of Fluid Properties of Thin Sand-Shale Interbedded Reservoirs Using Rock Physics–Based Frequency-Dependent AVO Analysis

Seismic frequency characters analysis for recognition of hydrocarbon reservoirs has become more popular. In this abstract, we focus on explaining frequency-dependent amplitude versus offset of thin sand-shale interbedded reservoirs, by quantifying the effect of anisotropy arising in a thin interlayer reservoirs and fluid-properties saturated in sandstones on seismic responses. A set of physical modelling were conducted and rock physical theoretical experiments were carried out based on the materials properties of physical model, in order to facilitate understanding of the underlying physical reason. The result of our analysis shows that the frequency-dependent amplitude versus offset properties calculated using the singular value decomposition (SVD) can be used to identify the fluid properties of thin sand-shale interlayer reservoirs. The fluid property of porous layers does change the frequency-dependent amplitude versus offset. The agreement between the physical modelling and theoretical results is quite well, demonstrates that frequency-dependent amplitude versus offset is a reliable seismic indictor for detecting fluid properties in thin interlayer reservoirs, especially in gas-bearing reservoirs.