Résumé
Because measuring the frequency dependence of elastic properties in the laboratory is a technical challenge, not enough experimental data exist to test the existing theories. We report measurements of three fluid‐saturated sandstones over a broad frequency band: Wilkenson, Berea, and Bentheim sandstones. Those sandstones samples, chosen for their variable porosities and mineral content, are saturated by fluids of varying viscosities. The samples elastic response (Young's modulus and Poisson's ratio) and hydraulic response (fluid flow out of the sample) are measured as a function of frequency. Large dispersion and attenuation phenomena are observed over the investigated frequency range. For all samples, the variation at lowest frequency relates to a large fluid flow directly measured out of the rock samples. These are the cause (i.e., fluid flow) and consequence (i.e., dispersion/attenuation) of the transition between drained and undrained regimes. Consistently, the characteristic frequency correlates with permeability for each sandstone. Beyond this frequency, a second variation is observed for all samples, but the rocks behave differently. For Berea sandstone, an onset of dispersion/attenuation is expected from both Young's modulus and Poisson's ratio at highest frequency. For Bentheim and Wilkenson sandstones, however, only Young's modulus shows dispersion/attenuation phenomena. For Wilkenson sandstone, the viscoelastic‐like dispersion/attenuation response is interpreted as squirt flow. For Bentheim sandstone, the second effect does not fully follow such response, which could be due to a lower accuracy in the measured attenuation or to the occurence of another physical effect in this rock sample. Plain Language Summary Field seismic is a powerful tool to investigate materials placed in locations where the eye cannot reach. From the measured elastic properties, one infers the rocks and saturating fluids at depths. This tool, however, relies on the understanding of the waves propagation through a given rock, in which knowledge is usually acquired from measurements in the laboratory. When comparing laboratory to field measurements, one major factor is the frequency of the wave traveling through the medium: at the megahertz in the laboratory, and below the kilohertz at the field scale. Our work aims at investigating experimentally the frequency dependence of the elastic properties in fluid‐saturated sandstones. We show that, if the pore fluid pressure is large, the dispersion/attenuation effects over the frequency range can be very large: large differences in elastic properties are expected if the same rock is measured in the lab or on the field. Separating the different physical effects, we show that two main phenomena occur in fluid‐saturated sandstones. Key Points Dispersions and attenuations over seismic frequency range in fluid‐saturated sandstones Clear observation of the Biot‐Gardner flow for all samples Different behavior in the high‐frequency range for the different sandstones