Laboratory Measurements of Seismic Attenuation from 0.01 to 100 Hz

The study of wave attenuation in partially saturated porous rocks over a broad frequency range provides valuable information about the fluid system of reservoirs, which are inherently multiple phase fluid systems. Until now, not much laboratory data have been collected in the seismically relevant low frequency range and existing literature data on experimental measured partially saturated rock are very limited. The main goal of our work is to experimentally measure the bulk seismic attenuation on fluid-bearing rocks, using natural rock samples in an efficient way at in situ conditions and employing linear variable differential transformers (LVDTs). We are currently fine-tuning our attenuation measurement prototype. Bench-top results are promising and show consistency with reported experimental data for dry, partially, and fully fluid saturated rocks. Measurements with the machine are accurate and precise. We are able to detect a wide range of attenuation values, from nearly elastic materials, like aluminum, up to very well characterized viscoelastic material, such as Plexiglas. This can be considered the end-members for a saturated rock in the low frequency range at different degrees of saturation.