Pradeep Bhattad, Chemical Engineering, Louisiana State University, 110 Chemical Engineering, South Stadium Road, Baton Rouge, LA 70803, Karsten E. Thompson, Gordon & Mary Cain Department of Chemical Engineering, Louisiana State University, 110 Chemical Engineering, South Stadium Rd, Baton Rouge, LA 70803, and Clinton S. Willson, Department of Civil & Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803.
Invasion of a wetting fluid into a porous medium (imbibition) is governed by the competition between the viscous and the capillary forces. This coupled with the complex pore structure leads to a variety of pore-filling mechanisms, which are well documented in literature. One of the main questions that is not yet well understood is the role of wetting films (wetting fluid ahead of the bulk front) in the invasion patterns. Although synchrotron x-ray microtomography has provided new insights into equilibrium phenomena, it is not able to provide information about the transient invasion processes because of the relatively long scan times (order of 10-60 minutes) compared to the dynamics. In this study, we use a novel approach to rapidly polymerize an imbibtion front during imbibition. 3D x-ray tomography is then used to quantitatively image the invasion patterns. We have studied three types of packing materials, namely, spheres, quartz sand and cylinders. For each packing material spontaneous imbibition curves were generated, and initial, intermediate and final flow rates were calculated. These rates were used in an investigation of imbibition dynamics in which three-dimensional images of the wetting fronts were obtained using XCT. We report on the effect of material structure on the dynamics of the front, the differences between equilibrium and, and on the nature of the wetting phase ahead of the bulk front.