Characterization of the crossover from capillary invasion to viscous fingering to fracturing during drainage in a vertical 2D porous medium

2014 ◽  
Vol 58 ◽  
pp. 279-291 ◽  
Author(s):  
Amina Islam ◽  
Sylvie Chevalier ◽  
Imen Ben Salem ◽  
Yves Bernabe ◽  
Ruben Juanes ◽  
...  
1999 ◽  
Vol 26 (1-2) ◽  
pp. 153-160 ◽  
Author(s):  
M.-N. Pons ◽  
E. M. Weisser ◽  
H. Vivier ◽  
D. V. Boger

Author(s):  
Eslam Ezzatneshan ◽  
Reza Goharimehr

In the present study, a pore-scale multicomponent lattice Boltzmann method (LBM) is employed for the investigation of the immiscible-phase fluid displacement in a homogeneous porous medium. The viscous fingering and the stable displacement regimes of the invading fluid in the medium are quantified which is beneficial for predicting flow patterns in pore-scale structures, where an experimental study is extremely difficult. Herein, the Shan-Chen (S-C) model is incorporated with an appropriate collision model for computing the interparticle interaction between the immiscible fluids and the interfacial dynamics. Firstly, the computational technique is validated by a comparison of the present results obtained for different benchmark flow problems with those reported in the literature. Then, the penetration of an invading fluid into the porous medium is studied at different flow conditions. The effect of the capillary number (Ca), dynamic viscosity ratio (M), and the surface wettability defined by the contact angle (θ) are investigated on the flow regimes and characteristics. The obtained results show that for M<1, the viscous fingering regime appears by driving the invading fluid through the pore structures due to the viscous force and capillary force. However, by increasing the dynamic viscosity ratio and the capillary number, the invading fluid penetrates even in smaller pores and the stable displacement regime occurs. By the increment of the capillary number, the pressure difference between the two sides of the porous medium increases, so that the pressure drop Δp along with the domain at θ=40∘ is more than that of computed for θ=80∘. The present study shows that the value of wetting fluid saturation Sw at θ=40∘ is larger than its value computed with θ=80∘ that is due to the more tendency of the hydrophilic medium to absorb the wetting fluid at θ=40∘. Also, it is found that the magnitude of Sw computed for both the contact angles is decreased by the increment of the viscosity ratio from Log(M)=−1 to 1. The present study demonstrates that the S-C LBM is an efficient and accurate computational method to quantitatively estimate the flow characteristics and interfacial dynamics through the porous medium.


Author(s):  
Patrick Grosfils ◽  
Jean Pierre Boon ◽  
Jonathan Chin ◽  
Edo S. Boek
Keyword(s):  

Author(s):  
H. L. Pan ◽  
O. Pickena¨cker ◽  
D. Trimis

In this paper, a method for the experimental characterization of the equivalent pore diameter of highly porous open structures is presented. The commonly used characterization of such structures through geometrical properties like ppi number (porous per inch) and porosity proves to be not sufficient for the characterization of length scales related to heat and mass transfer. The procedure used here utilizes the quenching limits for flame propagation as characterization criterion. The determined equivalent pore diameter corresponds to the quenching diameter for a tube-geometry filled with the same combustible mixture. The quenching limit was determined by adjusting critical conditions, which are defined by a constant critical Pe´clet number comprising the laminar flame velocity instead of the flow velocity. Variations of oxygen content and air ratio were used in order to change the laminar flame speed and find the quenching limit for a given porous medium. The equivalent pore diameter determined with this method is a characteristic length scale of the porous medium geometry and is related to the heat transfer between the gas phase and the solid porous structure. The validation of the method was performed on sphere packings with well-documented properties. Several practically relevant highly porous media like foams and fabric lamellae structures were characterized and the results are discussed. Based on the effective heat conductivity (EHC) models of Zehner, Bauer and Schlu¨nder [1–3] for packed beds, an adapted model for foam structures was developed. The adapted model utilizes the equivalent pore diameters determined in the paper and predictions are presented.


2010 ◽  
Vol 65 (7) ◽  
pp. 2284-2291 ◽  
Author(s):  
S. Swernath ◽  
B. Malengier ◽  
S. Pushpavanam

1984 ◽  
Vol 24 (03) ◽  
pp. 325-327 ◽  
Author(s):  
L. Paterson ◽  
V. Hornof ◽  
G. Neale

Abstract This paper discusses the viscous fingering that occurs when water or a surfactant solution displaces oil in a porous medium. Such floods were visualized in an porous medium. Such floods were visualized in an oil-wet porous medium composed of fused plastic particles. The flow structure changed significantly within the range of capillary numbers between 10 -4 and 10 -3 . The addition of surfactant resulted in narrower fingers, which developed in a more dispersive fashion. Introduction In describing fluid/fluid displacements in porous media, a useful dimensionless quantity is the capillary number, (1) which corresponds to the ratio of viscous forces to capillary forces. Here, v is the specific fluid discharge or Darcy velocity, it is viscosity, and o is interfacial tension (IFT). It has been shown that the recovery of oil from an underground reservoir increases significantly if the capillary number can be increased beyond the range of 1 × 10 -4 to 2 × 10 -3 during water flooding (see Larson et al. 1 ). To this end, surfactants are used extensively in tertiary oil recovery operations with the objective of reducing IFT and consequently mobilizing the oil ganglia which otherwise would remain trapped. This paper is concerned with the viscous fingering that occurs when water displaces oil in a porous medium, and we present a brief consideration on the effects that surfactants have on fingering. Noting that Peters and Flock have visualized fingering within the range of capillary numbers between 1.6 × 10 -6 and 7.2 × 10 -4, we present here visualizations at capillary numbers of 7.7 × 10 5 and 1.0 × 10 -3. Both our visualizations and the experiments of Peters and Flock involve large viscosity ratios so that only the viscosity of the more viscous fluid is considered when determining the capillary number. In particular, it is observed that as the capillary number increases, ganglia or blobs of displacing fluid are created at the displacement front in correspondence with the capillary numbers at which trapped ganglia are mobilized. This creation of ganglia at capillary numbers above 10 -3 was noted briefly in a previous paper 3 in which heptane displacing glycerine previous paper 3 in which heptane displacing glycerine was described. A secondary objective of this work was to test the Chuoke et al. theory for predicting the wavelength of fingers, wavelength being the peak-to-peak distance between adjacent well-developed fingers. Experimental Procedure The apparatus for these studies was described in Ref. 3. Basically, it consists of a slab of consolidated plastic particles 1.34 × 0.79 × 0.0 1 8 ft [0.44 × 0.26 × 0.006 m] with particles 1.34 × 0.79 × 0.0 1 8 ft [0.44 × 0.26 × 0.006 m] with a porosity of 0.43 and a permeability of 7, 100 darcies. This high permeability, when compared with that of reservoir rocks, should not be important for this study since capillary numbers and residual saturations are independent of pore size. Water (viscosity 1 cp [1 mPa s]) was used to displace paraffin oil (viscosity 68 cp 168 mPa s] at 77F [25C]). The water was dyed with methylene blue (which acts as a mild surfactant). Without the dye, the oil/water IFT was 42 dyne/cm [42 mN/m]. The addition of dye lowered this value to 36 dyne/cm [36 mN/m] for the concentration of dye used. For the surfactant flood, a 1 % sodium alkyl aryl sulfonate solution was used, giving a surfactant-solution/paraffin-oil IFT of 3.0 dyne/cm [3.0 mN/m]. Water Displacing Oil To compare our experiments with previous investigations of fingering, the displacement of paraffin oil by water at an average specific fluid discharge of 1.34 × 10–4 ft/sec [4.1 × 10 -5 m/s], corresponding to a capillary number of 7.7 × 10 -5, was studied (Fig. 1). Chuoke et al .4 and later Peters and Flock 2 have presented a formula for predicting the wavelength of presented a formula for predicting the wavelength of finger, lambda m : (2) where k is permeability, C is a dimensionless parameter which Peters and Flock call the wettability number and suggest would have the value 25 for an oil-wet porous medium, and mu o and mu ware viscosities of the displaced oil and displacing water, respectively. It was observed that the plastic particles of the porous medium considered here were oil wet because of adsorption of oil. SPEJ P. 325


Fractals ◽  
2008 ◽  
Vol 16 (02) ◽  
pp. 109-117
Author(s):  
H. SHAIKH YUSUF ◽  
A. R. KHAN ◽  
S. H. BEHERE

The study of the viscous fingering in Hele Shaw cell and the evolution of fingering pattern was presented and the growth velocity of pattern was determined. The fingers were recorded using a digital web camera. The movie frames were separated and the selected patterns were analyzed. The box counting technique was applied to the growth pattern and the Richardson plot technique was used for characterization of shapes in terms of structure and texture. The fingering patterns thus obtained in different frames were analyzed and the structural and textural analysis was presented. The scale invariance at different length scales was discussed.


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