Influence of Fluid Distribution on Seismic Dispersion and Attenuation in Partially Saturated Limestone

Quantitatively assessing attenuation and dispersion of elastic-wave velocities in partially saturated reservoir is difficult because its sensitivity to fluid distribution. We conducted experiments on homogeneous Indiana limestone samples, by two methods: drying imbibition which lead different distribution for a given saturation. Forced oscillations (from 0.004 100 Hz) ultrasonic (1 MHz) measurements were done under confining pressure measure the change elastic moduli with frequency their attenuation. Our show that compressional (P-)velocities are strongly sensitive sample’s saturation method. For high saturations (above 80%), obtained drainage, dependent, clear peaks can be observed. However, at same imbibition, no or In addition, shear little variation frequency, saturations, The P-velocities shown influenced pore distribution, was investigated using micro-computer-assisted tomographic (CT) scans. Furthermore, numerical model developed within framework poroelasticity’s theory predicts well experimental results, from CT as an input. results velocity related wave-induced flow mesoscopic scale controlled geometry gas patches.