Experimental study on imbibition displacement mechanisms of two-phase fluid using micro model

Abstract

This study applies a transparent micro model and digital image analysis to the experimental study of the displacement mechanisms for water and air in porous media during imbibition process, and examines the displacement formulas. This study conducts experiments following Lenormand's assumptions as closely as possible. Various displacement mechanisms were observed, and their images were recorded. The displacement mechanisms in imbibition are mainly snap-off, In type imbibition and piston-type motion. The experimental fluid displacement images and associated capillary pressure were then used to verify the displacement formulas. This experimental study shows that, when snap-off occurred, the experimental capillary pressures were close to the Lenormand's estimation of critical capillary pressures where enough surrounding area of the throat was saturated. When I1 and I2 type imbibitions occurred, the experimental capillary pressures were also close to the Lenormand's estimation of critical capillary pressures where enough connecting throats were saturated. The In type imbibition and its associated piston-type motions are the main processes to increase the wetting phase fluid saturation. For the pore-throat distribution applied in this study, snap-off can facilitate the occurrence of In type imbibition and its associated piston-type motion; therefore, snap-off is an important displacement mechanism in facilitating the increase of the wetting phase fluid saturation in the imbibition process. To summarize, this study provides valuable experimental support and suggestions for Lenormand's displacement formulas, which are the basis for many related experimental and numerical studies.

Modelling Energy Dissipation Due to Soil-Moisture Hysteresis

“…hence Figure 7 shows the dependence of the energy dissipation I = I(ω) on the frequency of forcing (11). The plot is obtained numerically with the interactive applet, which is available at the web site [29].…”

“…A class of Preisach models with few parameters proposed in [3] has been shown to fit field empirical data more accurately than the model based on Parlange approach, which was used in [10]. Recent experimental and theoretical research of multiphase flows, including laboratory measurements on model porous networks, reveal complex microscopic mechanisms of fluids displacement in the pores which underlie the hysteresis effect and lead to new methods of its quantification, see [8,11] and references therein. These models are more physical but also more complicated than the Preisach description of the sorption hysteresis adopted here.…”

Waterflooding of Surfactant and Polymer Solutions in a Porous Media Micromodel

“…In this approach, an optically transparent flow cell is constructed with a uniform distribution of glass or quartz beads dispersed inside to act as the porous grain structure, and direct visualization of the flow is then performed using optical microscopy techniques [17,18]. Although advances in microfabrication technology allow for the manufacturing of complex pore structures [19], most micromodels used to study multiphase fluid flow through pore media have been done in rectangular pore bodies and throats [16,[20][21][22][23][24][25]. Computer-aided design of microchannels [26,27] can be used to mimic heterogeneous porous media structure.…”

On the fabrication of PDMS micromodels by rapid prototyping, and their use in two‐phase flow studies

“…[4] Micromodels have been mostly used in studying displacements of two immiscible fluid phases in porous media [Chang et al, 2009;Corapcioglu et al, 2009;Avraam et al, 1994;Baouab et al, 2007, NagaSiva et al, 2011. Processes of drainage and imbibition, as well as the mechanisms that dominate them, like viscous or capillary fingering, snap-off, etc., have been studied using micromodels [Zhang et al, 2011;Ferer et al, 2004;Grate et al, 2010;Gutierrez et al, 2008;Hug et al, 2003;Huh et al, 2007].…”