Experimental study of the effects of hydraulic gradient and injected-gas flow rate on fragmentation in porous media

Water Resources Research

Hassanizadeh

Niasar

et al. 2014

Recent computational studies of two-phase flow suggest that the role of fluid-fluid interfaces should be explicitly included in the capillarity equation as well as equations of motion of phases. The aim of this study has been to perform experiments where transient movement of interfaces can be monitored and to determine interfacial variables and quantities under transient conditions. We have performed two-phase flow experiments in a transparent micromodel. Specific interfacial area is defined, and calculated from experimental data, as the ratio of the total area of interfaces between two phases per unit volume of the porous medium. Recent studies have shown that all drainage and imbibition data points for capillary pressure, saturation, and specific interfacial area fall on a unique surface. But, up to now, almost all micromodel studies of two-phase flow have dealt with quasi-static or steady state flow conditions. Thus, only equilibrium properties have been studied. We present the first study of two-phase flow in an elongated PDMS micromodel under transient conditions with high temporal and spatial resolutions. We have established that different relationships between capillary pressure, saturation, and specific interfacial area are obtained under steady state and transient conditions. The difference between the surfaces depends on the capillary number. Furthermore, we use our experimental results to obtain average (macroscale) velocity of fluid-fluid interfaces and the rate of change of specific interfacial area as a function of time and space. Both terms depend on saturation nonlinearly but show a linear dependence on the rate of change of saturation. We also determine macroscale material coefficients that appear in the equation of motion of fluid-fluid interfaces. This is the first time that these parameters are determined experimentally.

Section: Introductionmentioning

confidence: 98%

Micromodel study of two‐phase flow under transient conditions: Quantifying effects of specific interfacial area

Water Resources Research

Hassanizadeh

Niasar

et al. 2014

“…9). The fabrication technique is based on chemical reactions and the interaction of laser and plasma radiation with glass, silicon, or polymer (Zhang et al, 2010, 2011a, 2011b; Baouab et al, 2007; Gutiérrez et al, 2008; Soudmand‐asli et al, 2007; Weidman and Joshi, 1993; Jeong and Corapcioglu, 2003, 2005; Baumann et al, 2002; Lanning and Ford, 2002; McKellar and Wardlaw, 1982). First, the desired pattern for the micromodel is produced with one of the methods mentioned above.…”

Section: Fabrication Of Micromodelsmentioning

confidence: 99%

“…The majority of the applications of micromodels in studies of flow and transport in porous media are related to the immiscible displacement of two fluid phases (Avraam et al, 1994; Baouab et al, 2007; Dawe et al, 2010, 2011; Budwig, 1994; Chatenever and Calhoun, 1952; Chen and Wilkinson, 1985; Chuoke et al, 1959; Corapcioglu et al, 2009; Coskuner, 1997; Cottin et al, 2011; Crandall et al, 2009; de Zélicourt et al, 2005; Tóth et al, 2007; Tsakiroglou and Avraam, 2002; van der Marck and Glas, 1997; Wan et al, 1996; Chang et al, 2009a, 2009b; Theodoropoulou et al, 2005; Berejnov et al, 2008; Tsakiroglou et al, 2003a, 2003b, 2007). 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, 2011a, 2011b; Ferer et al, 2004; Grate et al, 2010; Gutiérrez et al, 2008; Hug et al, 2003; Huh et al, 2007; Jeong and Corapcioglu, 2003, 2005; Jeong et al, 2000; Lovoll et al, 2005; Mattax and Kyte, 1961; Montemagno and Gray, 1995; Pyrak‐Nolte et al, 1988; Rangel‐German and Kovscek, 2006; Stöhr et al, 2003; Sugii and Okamoto, 2004; Tallakstad et al, 2009; Lenormand and Zarcone, 1985a, 1985b; Lenormand, 1989a, 1989b; Lenormand et al, 1988; Sharma et al, 2011; Romano et al, 2011; Frette et al, 1997).…”

Section: Applications Of Micromodels In Studies Of Flow and Transportmentioning

confidence: 99%

A Review of Micromodels and Their Use in Two-Phase Flow Studies

Hassanizadeh

2012

Vadose Zone Journal

202

143

During the last 25 to 30 yr , micromodels have been increasingly used to study the behavior of fl uids inside microstructures in various research areas. Studies have included chemical, biological, and physical applica ons. Micromodels have proven to be a valuable tool by enabling us to observe the fl ow of fl uids and transport of solutes within the pore space. They have helped to increase our insight into fl ow and transport phenomena on both micro-and macro-scales. In this review, we have considered only the applica on of micromodels in the study of two-phase fl ow in porous media. Various methods exist for genera ng pa erns used in micromodels. These include perfectly regular pa erns, par ally regular pa erns, fractal pa erns, and irregular pa erns. Various fabrica on methods and materials are used in making micromodels, each with its own advantages and disadvantages. The major fabrica on methods include: Hele-Shaw; glass beads; op cal lithography; wet, dry, and laser or plasma etching; stereo lithography, and so lithography. The distribu on of phases in micromodels can be visualized using (confocal) microscopes, digital cameras, or their combina on. Micromodels have been applied to the study of twophase displacement processes, measurements of fl uid-fl uid interfacial area and phase satura on, measurements of rela ve permeability, and the study of enhanced oil recovery.

“…[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].…”

Section: Introductionmentioning

confidence: 99%

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

Water Resources Research

Musterd

Kleingeld

et al. 2013

[1] Micromodels have been increasingly employed in various ways in porous media research, to study the pore-scale behavior of fluids. Micromodels have proven to be a valuable tool by allowing the observation of flow and transport at the micron scale in chemical, biological, and physical applications. They have helped to improve our insight of flow and transport phenomena at both microscale and macroscale. Up to now, most micromodels that have been used to study the role of interfaces in two-phase flow were small, square, or nearly square domains. In this work, an elongated PDMS micromodel, bearing a flow network with dimensions 5Â30 mm 2 was manufactured. The pore network was designed such that the REV size was around 5Â7 mm 2 . So, our flow network was considered to be nearly four times the REV size. Using such micromodels, we established that the inclusion of interfacial area between the wetting and the nonwetting fluids models the hysteretic relationship between capillary pressure and saturation in porous media. In this paper, we first present the procedure for manufacturing PDMS micromodels with the use of soft lithography. Then, we describe an innovative and novel optical setup that allows the real-time visualization of elongated samples. Finally, we present the results obtained by quasi-static, two-phase flow experiments.