Simulating drainage and imbibition experiments in a high‐porosity micromodel using an unstructured pore network model

Abstract

[1] Development of pore network models based on detailed topological data of the pore space is essential for predicting multiphase flow in porous media. In this work, an unstructured pore network model has been developed to simulate a set of drainage and imbibition laboratory experiments performed on a two-dimensional micromodel. We used a pixel-based distance transform to determine medial pixels of the void domain of micromodel. This process provides an assembly of medial pixels with assigned local widths that simulates the topology of the porous medium. Using this pore network model, the capillary pressure-saturation and capillary pressure-interfacial area curves measured in the laboratory under static conditions were simulated. On the basis of several imbibition cycles, a surface of capillary pressure, saturation and interfacial area was produced. The pore network model was able to reproduce the distribution of the fluids as observed in the micromodel experiments. We have shown the utility of this simple pore network approach for capturing the topology and geometry of the micromodel pore structure.Citation: Joekar Niasar, V., S. M. Hassanizadeh, L. J. Pyrak-Nolte, and C. Berentsen (2009), Simulating drainage and imbibition experiments in a high-porosity micromodel using an unstructured pore network model, Water Resour. Res.,

Uniqueness of Specific Interfacial Area–Capillary Pressure–Saturation Relationship Under Non-Equilibrium Conditions in Two-Phase Porous Media Flow

“…In addition to this advantage, pore-network modeling was applied successfully for many two-phase flow problems. Specifically, this study found good agreement between modeling and experimental results for the relationship of capillary pressure, saturation, and interfacial area under drainage and imbibition under equilibrium conditions (Joekar-Niasar et al 2009, 2010b. Finally, given the idealization of the geometries of porous media and interfaces, their description is based on an infinite resolutions, which prevents errors introduced by the discretization of the geometries.…”

“…The average absolute relative errors are ∓8.5% and ∓17.5% for total specific interfacial area and main terminal interfacial area, respectively. In previous studies, a simple quadratic polynomial equation has been fitted to such a surface (Joekar-Niasar et al 2009;Porter et al 2009). However, the polynomial equations are not restricted within the physical range of variation.…”

“…The authors' previous studies investigated the validity of this theory under equilibrium conditions. In the study of Joekar-Niasar et al (2009), micromodel two-phase flow experiments were simulated using a medial-axis based pore-network model. The pore-network model results match well with the experimental data not only for P c -S w but also for a nw -S w curves.…”

Hysteresis and interfacial energies in smooth‐walled microfluidic channels

“…Although complex geometry and bifurcations are important contributors to the hysteresis in the P c -S w relationship for multiphase flow in porous media [Gray, 1999;Niasar et al, 2009], in our study, the geometrical contribution has been eliminated. Therefore, the phase occupancy is dominated only by the surface tension, and thus the hysteresis must be entirely determined by the surface chemistry.…”

“…Computational modeling and experimental validation consistent with the theory have been performed on various multiphase porous systems with complex geometries [Cheng et al, 2004;Culligan et al, 2004;Chen et al, 2007;Joekar-Niasar et al, 2008;Niasar et al, 2009;Porter et al, 2009]. Helland and Skjaeveland considered contact angle hysteresis to investigate the P c -S w -a wn relationship [Helland and Skjaeveland, 2007].…”