Enhancement of velocity contrasts by shear-thinning solutions flowing in a rough fracture

Auradou, Harold; Boschan, Alejandro; Chertcoff, R.; Gabbanelli, S.; Hulin, Jean-Pierre; Ippolito, I.

doi:10.1016/j.jnnfm.2007.11.008

Cited by 34 publications

(20 citation statements)

References 27 publications

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“…In section 3.2, the transition Péclet number Pe * between these two regimes has been estimated for the faster channels between the obstacles; the corresponding values are Pe * 10 and Pe * 30 respectively for the 1000 ppm and 500 ppm solution. For a variation of Pe from Pe ≪ Pe * to Pe ≫ Pe *, α G should increase from the same value as for a Newtonian fluid toward the higher one discussed above [ Auradou et al , 2008]. Since the above estimations of Pe * are within the experimental range, the coefficients α G obtained from a fit of the variation of l d / a over data points corresponding to all Péclet numbers will therefore be intermediate between the values for Newtonian and power law fluids as is indeed observed.…”

Section: Local Spreading Of the Mixing Zonementioning

confidence: 99%

Geometrical and Taylor dispersion in a fracture with random obstacles: An experimental study with fluids of different rheologies

Boschan

Ippolito

Chertcoff

et al. 2008

Water Resources Research

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[1] The miscible displacement of a Newtonian or shear-thinning fluid by another one of same rheological properties has been studied optically in a flat transparent model fracture with a random distribution of identical cylindrical obstacles on one of the walls. At the local scale, the concentration variation on individual pixels satisfies a Gaussian convection-dispersion relation with local transit time t(x, y) and dispersivity l d (x, y). The variation of l d with the Péclet number Pe shows that it results from a combination of geometrical and Taylor dispersion, respectively dominant at low and high Pe values. Using shear-thinning solutions instead of a Newtonian fluid enhances the velocity contrasts (and therefore geometrical dispersion) and reduces Taylor dispersion. At the global scale, the front geometry is studied from the isoconcentration lines c = 0.5 (equivalent to lines of constant t(x, y) value): beyond a transition travel time, their width in the direction parallel to the flow reaches a constant limit varying linearly with Log(Pe) with a slope increasing with the shear-thinning character of the fluid. These characteristics are compared to previous observations on other model fractures with a self-affine roughness displaying channelization effects.

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Section: Local Spreading Of the Mixing Zonementioning

confidence: 99%

Geometrical and Taylor dispersion in a fracture with random obstacles: An experimental study with fluids of different rheologies

Boschan

Ippolito

Chertcoff

et al. 2008

Water Resources Research

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“…Permeability contrasts have significant effects during EOR projects in which the injected EOR agent tends to flow within the fracture network rather than sweep the oil-saturated matrix blocks (Manrique et al 2007). In addition, oil is retained in the rock matrix by capillary forces in oil-wet formations (Hirasaki and Zhang 2004), but can be produced by either reducing the interfacial tension (IFT) or changing the matrix wettability using additives in the water including surfactants (Seethepalli et al 2004) or sulfate (Austad and Standnes 2003). EOR techniques in fractured reservoirs rely on maximizing the contact area between the injected EOR fluid and the rock surface, and therefore the EOR fluid must transport effectively within the fracture network (Zuta and Fjelde 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Heterogeneous fracture networks may therefore result in poor sweep of the injected EOR fluid, and mobility control should be implemented to maximize contact. Two-phase flow within roughwalled fractures was previously investigated with Newtonian fluids (Pruess and Tsang 1990;Fourar et al 1993;Chen and Horne 2006) and non-Newtonian polymer solutions (Di Federico 1997;Auradou et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Foam Generation, Sweep Efficiency, and Flow in a Fracture Network

et al. 2016

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Foam generation for gas mobility reduction in porous media is a well-known method and frequently used in field applications. Application of foam in fractured reservoirs has hitherto not been widely implemented, mainly because foam generation and transport in fractured systems are not clearly understood. In this laboratory work, we experimentally evaluate foam generation in a network of fractures within fractured carbonate slabs. Foam is consistently generated by snap-off in the rough-walled, calcite fracture network during surfactant-alternating-gas (SAG) injection and coinjection of gas and surfactant solution over a range of gas fractional flows. Boundary conditions are systematically changed including gas fractional flow, total flow rate, and liquid rates. Local sweep efficiency is evaluated through visualization of the propagation front and compared for pure gas injection, SAG injection, and coinjection. Foam as a mobility-control agent resulted in significantly improved areal sweep and delayed gas breakthrough. Gas-mobility reduction factors varied from approximately 200 to more than 1,000, consistent with observations of improved areal sweep. A shear-thinning foam flow behavior was observed in the fracture networks over a range of gas fractional flows.

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“…As a first simple approach similar to the one presented by Auradou et al . [], we will assume that the fracture space can be modeled as being a bundle of parallel rectangular canals of length L, width w i , and aperture h i , with w i » h i . h i is expected to vary along the flow paths.…”

Section: Discussionmentioning

confidence: 99%

Flow of yield stress and Carreau fluids through rough‐walled rock fractures: Prediction and experiments

Castro

Radilla

2017

Water Resources Research

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Many natural phenomena in geophysics and hydrogeology involve the flow of non‐Newtonian fluids through natural rough‐walled fractures. Therefore, there is considerable interest in predicting the pressure drop generated by complex flow in these media under a given set of boundary conditions. However, this task is markedly more challenging than the Newtonian case given the coupling of geometrical and rheological parameters in the flow law. The main contribution of this paper is to propose a simple method to predict the flow of commonly used Carreau and yield stress fluids through fractures. To do so, an expression relating the “in situ” shear viscosity of the fluid to the bulk shear‐viscosity parameters is obtained. Then, this “in situ” viscosity is entered in the macroscopic laws to predict the flow rate‐pressure gradient relations. Experiments with yield stress and Carreau fluids in two replicas of natural fractures covering a wide range of injection flow rates are presented and compared to the predictions of the proposed method. Our results show that the use of a constant shift parameter to relate “in situ” and bulk shear viscosity is no longer valid in the presence of a yield stress or a plateau viscosity. Consequently, properly representing the dependence of the shift parameter on the flow rate is crucial to obtain accurate predictions. The proposed method predicts the pressure drop in a rough‐walled fracture at a given injection flow rate by only using the shear rheology of the fluid, the hydraulic aperture of the fracture, and the inertial coefficients as inputs.

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Enhancement of velocity contrasts by shear-thinning solutions flowing in a rough fracture

Cited by 34 publications

References 27 publications

Geometrical and Taylor dispersion in a fracture with random obstacles: An experimental study with fluids of different rheologies

Geometrical and Taylor dispersion in a fracture with random obstacles: An experimental study with fluids of different rheologies

Experimental Study of Foam Generation, Sweep Efficiency, and Flow in a Fracture Network

Flow of yield stress and Carreau fluids through rough‐walled rock fractures: Prediction and experiments

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