Challenges in modeling unstable two-phase flow experiments in porous micromodels

Details

Serval ID
serval:BIB_33789079EB5D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Challenges in modeling unstable two-phase flow experiments in porous micromodels
Journal
Water Resources Research
Author(s)
Ferrari Andrea, Jimenez-Martinez Joaquin, Borgne Tanguy Le, Méheust Yves, Lunati Ivan
ISSN
0043-1397
Publication state
Published
Issued date
03/2015
Peer-reviewed
Oui
Volume
51
Number
3
Pages
1381-1400
Language
english
Abstract
The simulation of unstable invasion patterns in porous media flow is very challenging because small perturbations are amplified, so that slight differences in geometry or initial conditions result in significantly different invasion structures at later times. We present a detailed comparison of pore-scale simulations and experiments for unstable primary drainage in porous micromodels. The porous media consist of Hele-Shaw cells containing cylindrical obstacles. By means of soft lithography, we have constructed two experimental flow cells, with different degrees of heterogeneity in the grain size distribution. As the defending (wetting) fluid is the most viscous, the interface is destabilized by viscous forces, which promote the formation of preferential flow paths in the form of a branched finger structure. We model the experiments by solving the Navier-Stokes equations for mass and momentum conservation in the discretized pore space and employ the Volume of Fluid (VOF) method to track the evolution of the interface. We test different numerical models (a 2-D vertical integrated model and a full-3-D model) and different initial conditions, studying their impact on the simulated spatial distributions of the fluid phases. To assess the ability of the numerical model to reproduce unstable displacement, we compare several statistical and deterministic indicators. We demonstrate the impact of three main sources of error: (i) the uncertainty on the pore space geometry, (ii) the fact that the initial phase configuration cannot be known with an arbitrarily small accuracy, and (iii) three-dimensional effects. Although the unstable nature of the flow regime leads to different invasion structures due to small discrepancies between the experimental setup and the numerical model, a pore-by-pore comparison shows an overall satisfactory match between simulations and experiments. Moreover, all statistical indicators used to characterize the invasion structures are in excellent agreement. This validates the modeling approach, which can be used to complement experimental observations with information about quantities that are difficult or impossible to measure, such as the pressure and velocity fields in the two fluid phases.
Keywords
Water Science and Technology
Web of science
Open Access
Yes
Funding(s)
Swiss National Science Foundation / PP00P2-123419
Swiss National Science Foundation / PP00P2-144922
Create date
10/02/2015 18:04
Last modification date
17/03/2023 6:51
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