ABSTRACT
While theoretical poroelastic models can predict the acoustic response for a given spatial distribution of fluid patches, the factors controlling the formation
of the patches are less well understood. These factors can be studied using fluid-injection experiments in the laboratory. Previously reported laboratory observations demonstrate a qualitative link between fluid patch distribution and acoustic velocities (Cadoret et al. 1995, 1998; Monsen & Johnstad 2005). In order to get a deeper insight into the factors influencing the patch distribution and the associated wave response, we perform simultaneous measurements of P-wave velocities and rock sample X-ray computer tomography (CT) imaging. The CT imaging allows us to infer the fluid distribution inside the rock sample during saturation (water imbibition). We then show that the experimental results are consistent with theoretical predictions and numerical simulations.
