We study wave-induced fluid flow effects in porous rocks partially
saturated with gas and water, where the saturation patterns are governed
by mesoscopic heterogeneities associated with the dry frame properties.
The link between the dry frame properties and the gas saturation
is defined by the assumption of capillary pressure equilibrium, which
in the presence of heterogeneity implies that neighboring regions
can exhibit different levels of saturation. In order to determine
the equivalent attenuation and phase velocity of the synthetic rock
samples considered in this study, we apply a numerical upscaling
procedure, which permits to take into account mesoscopic heterogeneities
associated with the dry frame properties as well as spatially continuous
variations of the pore fluid properties. We consider numerical experiments
to analyze such effects in heterogeneous partially saturated porous
media, where the saturation field is determined by realistic variations
in porosity. Our results indicate that the spatially continuous nature
of gas saturation inherent to this study is a critical parameter
controlling the seismic response of these environments, which in
turn suggests that the physical mechanisms governing partial saturation
should be accounted for when analyzing seismic data in a poro-elastic
context.