Skip to main content
Log in

Capillary hyperdisperson of wetting liquids in fractal porous media

  • Published:
Transport in Porous Media Aims and scope Submit manuscript

Abstract

Recent displacement experiments show ‘anomalously’ rapid spreading of water during imbibition into a prewet porous medium. We explain this phenomenon, calledhyperdispersion, as viscous flow along fractal pore walls in thin films of thicknessh governed by disjoining forces and capillarity. At high capillary pressure, total wetting phase saturation is the sum of thin-film and pendular stucture inventories:S w =S tf +S ps . In many cases, disjoining pressure ∏ is inversely proportional to a powerm of film thicknessh, i.e. ∏ ∞h −m , so thatS tf P c −1/m. The contribution of fractal pendular structures to wetting phase saturation often obeys a power lawS ps P c (3−D), whereD is the Hausdorff or fractal dimension of pore wall roughness. Hence, if wetting phase inventory is primarily pendular structures, and if thin films control the hydraulic resistance of wetting phase, the capillary dispersion coefficient obeysD c S v w , where v=[3−m(4−D) ]/m(3−D). The spreading ishyperdispersive, i.e.D c (S w ) rises as wetting phase saturation approaches zero, ifm>3/(4−D),hypodispersive, i.e.D c (S 2) falls as wetting phase saturation tends to zero, ifm<3/(4−D), anddiffusion-like ifm=3/(4−D). Asymptotic analysis of the ‘capillary diffusion’ equation is presented.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Abbreviations

a :

Pre-exponential factor in power-law scaling ofD c withS w

b :

Exponent in power-law scaling ofD c withS w

B :

Ratio of gravitational forces to viscous forces

D :

Hausdorff or fractal dimension

D c :

Capillary dispersion coefficient (m2s−1)

f(r) :

Pore radius probability density function

F :

Fractional flow

G :

Mutual permeability (m3s Kg−1)

g :

Gravitational potential per unit mass (m s)

h :

Film thickness (m)

k :

Absolute permeability (m2)

k i :

Effective permeability of phasei(m2)

m :

Power law exponent of ∏ (h) in the limit of smallh

P c :

Capillary pressure,P nw P w (Pa)

P i :

Pressure in bulk phasei (Pa)

S :

Wetting phase saturation

t :

Time coordinate (s)

v :

Net flow velocity (m s−1)

x :

Spatial coordinate (m)

z :

Elevation (m)

γ :

Interfacial tension (N m−1)

δ:

Density contrast

λ :

Boltzmann transform

Μ i :

Viscosity of phasei (Kg m−1 s−1)

v :

Exponent in power-law scaling ofD c withS w

∏:

Disjoining pressure (Pa)

ρ i :

Density of phasei (Kg m−3)

σ 2 :

Variance of parent normal distribution

Φ :

Porosity

nw :

Nonwetting phase (oil, air)

ps :

Pendular structure

tf :

Thin film

w :

Wetting phase (water)

References

  • Bacri, J.-C., Leygnac, C., and Salin, D., 1985, Evidence of capillary hyperdiffusion in two-phase fluid flows,J. Phys. Lett. (Paris) 46, L467–473.

    Article  Google Scholar 

  • Bacri, J.-C., Leygnac, C., and Salin, D., 1984, Study of miscible fluid flows in a porous medium by an acoustical method,J. Phys. Lett. (Paris) 45, L767.

    Article  Google Scholar 

  • Brooks, R. H. and Corey, A. T., 1964, Hydraulic properties of porous media, Hydrology Paper No. 3, Colorado State University, Fort Collins.

    Google Scholar 

  • Crank J. and Henry, M. E., 1949a, Diffusion in media with variable properties: I,Trans. Faraday Soc. 45, 636–642.

    Article  Google Scholar 

  • Crank, J. and Henry, M. E., 1949b, Diffusion in media with variable properties: II,Trans. Faraday Soc. 45, 1119–1128.

    Article  Google Scholar 

  • Davis, H. T., 1989, On the fractal character of the porosity of natural sandstone,Europhys. Lett. 8, 629–632.

    Article  Google Scholar 

  • de Gennes, P. G., 1985, Partial filling of a fractal structure by a wetting fluid, in D. Adleret al. (eds),Physics of Disordered Materials, Plenum Press, New York, pp. 227–241.

    Chapter  Google Scholar 

  • Derjaguin, B. V. and Churaev, N. V., 1974, Structural component of disjoining pressure,J. Colloid Interface Sci. 49, 249–255.

    Article  Google Scholar 

  • Derjaguin, B. V. and Landau, L. D., 1941, Theory of stability of strongly charged lyophobic sols and of the adhesion of strongly charged particles in solutions of electrolytes,Acta Phys.-Chim. URSS. 14, 633–662.

    Google Scholar 

  • Feder, J., 1988,Fractals, Plenum, New York.

    Book  Google Scholar 

  • Gardner, W. R. and Mayhugh, M. S., 1958, Solution and tests of the diffusion equation for the movement of water in soils,Soil Sci. Soc. Am. Proc. 22, 197–201.

    Article  Google Scholar 

  • Hillel, D., 1971,Soil and Water: Physical Principles and Processes, Academic Press, New York.

    Google Scholar 

  • Jackson, R. D., 1964a, Water vapor diffusion in relatively dry soil: I. Theoretical considerations and sorption experiments,Soil Sci. Soc. Am. Proc. 27, 172–176.

    Article  Google Scholar 

  • Jackson, R. D., 1964b, Water Vapor diffusion in relatively dry soil: III. Steady state experiments,Soil. Sci. Soc. Am. Proc. 27, 467–470.

    Article  Google Scholar 

  • Katz, A. J. and Thompson, A. H., 1985, Fractal sandstone pores: Implications for conductivity and pore formation,Phys. Rev. Lett. 54, 1325–1328.

    Article  Google Scholar 

  • Klute, A., 1952, A numerical method for solving the flow equation for water in unsaturated materials,Soil Sci. 73, 105.

    Article  Google Scholar 

  • Melrose, J. C., 1988, Characterization of petroleum reservoir rocks by capillary pressure techniques, in K. K. Ungeret al. (eds.),Characterization of Porous Solids, Elsevier, Amsterdam, pp. 253–261.

    Google Scholar 

  • Mohanty, K. K., 1981, Fluids in porous media: Two-phase distribution and flow, PhD Thesis, University of Minnesota, Minneapolis.

    Google Scholar 

  • Novy, R. A., Toledo, P. G., Davis, H. T., and Scriven, L. E., 1989, Capillary dispersion in porous media at low wetting phase saturations,Chem. Eng. Sci. 44, 1785–1797.

    Article  Google Scholar 

  • Pashley, R. M., 1980, Multilayer adsorption of water on silica: An analysis of experimental results,J. Colloid Interface Sci. 78, 246–248.

    Article  Google Scholar 

  • Peaceman, D. W., 1977,Fundamentals of Numerical Reservoir Simulation, Elsevier-North-Holland, New York.

    Google Scholar 

  • Philip, J. R., 1955a, Numerical solution of equations with diffusivity concentration-dependent,Trans. Faraday Soc. 51, 885–892.

    Article  Google Scholar 

  • Philip, J. R., 1955b, The concept of diffusion applied to soil water,Proc. Natl. Acad. Sci. India A24, 93–104.

    Google Scholar 

  • Sahimi, M., 1984, Transport and dispersion in porous media and related aspects of petroleum recovery, PhD Thesis, University of Minnesota, Minneapolis.

    Google Scholar 

  • Toledo, P. G., Novy, R. A., Davis, H. T., and Scriven, L. E., 1990a, Hydraulic conductivity of porous media at low water content,Soil Sci. Soc. Am. J. 54, 673–679.

    Article  Google Scholar 

  • Toledo, P. G., Novy, R. A., Davis, H. T., and Scriven, L. E., 1990b, On the transport properties of porous media at low water content, in M. Th. van Genuchten (ed.),Indirect Methods for Estimating the Hydraulic Properties of Unsaturated Soils, Riverside, California.

  • Ward, J. S. and Morrow, N. R., 1987, Capillary pressure and gas relative permeabilities of low-permeability sandstone,Soc. Pet. Eng. Form. Eval. 1, 93–104.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Toledo, P.G., Ted Davis, H. & Scriven, L.E. Capillary hyperdisperson of wetting liquids in fractal porous media. Transp Porous Med 10, 81–94 (1993). https://doi.org/10.1007/BF00617512

Download citation

  • Received:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00617512

Key words

Navigation