TY - JOUR

T1 - Infiltration of DNAPL into heterogeneous water-saturated soil with different connectivity properties

AU - Neuweiler, Insa

AU - Cirpka, Olaf

AU - Eichel, Hartmut

AU - Helmig, Rainer

PY - 2004

Y1 - 2004

N2 - We consider the infiltration of DNAPL into heterogeneous water-saturated porous media. The heterogeneities are modeled as periodic continuously distributed permeability and capillary entry-pressure fields with log normal distribution. For the spatial correlation, we use different models: fields with a higher connectivity but similar two-point correlation function as introduced by [1], where one time the high permeable material is connected and one time the low permeable material is connected. For multi-phase flow, we assume capillary equilibrium, requiring that capillary forces dominate on the small scale. We determine the effective retention curve for the medium using a percolation approach. The relative permeability curves are obtained by solving the single-phase flow problem for the total permeability field at a given capillary pressure. Two different flow configurations are considered in order to obtain limiting cases for the effective parameter curves. Fields exhibiting connection of low absolute permeability values yield a lower effective residual saturation than fields originated from standard random-field generators. Due to the similarity of the covariance functions of the highly and poorly connected fields, the difference in residual saturation would not be obtained by linear stochastic theory. The two-point cluster function as introduced in [2], applied to an indicator field of the total permeability, is used in order to predict residual saturations and thus to make predictions about the effective parameter functions. Finally, we compare the results of numerical multiphase-flow simulations for the heterogeneous and upscaled fields.

AB - We consider the infiltration of DNAPL into heterogeneous water-saturated porous media. The heterogeneities are modeled as periodic continuously distributed permeability and capillary entry-pressure fields with log normal distribution. For the spatial correlation, we use different models: fields with a higher connectivity but similar two-point correlation function as introduced by [1], where one time the high permeable material is connected and one time the low permeable material is connected. For multi-phase flow, we assume capillary equilibrium, requiring that capillary forces dominate on the small scale. We determine the effective retention curve for the medium using a percolation approach. The relative permeability curves are obtained by solving the single-phase flow problem for the total permeability field at a given capillary pressure. Two different flow configurations are considered in order to obtain limiting cases for the effective parameter curves. Fields exhibiting connection of low absolute permeability values yield a lower effective residual saturation than fields originated from standard random-field generators. Due to the similarity of the covariance functions of the highly and poorly connected fields, the difference in residual saturation would not be obtained by linear stochastic theory. The two-point cluster function as introduced in [2], applied to an indicator field of the total permeability, is used in order to predict residual saturations and thus to make predictions about the effective parameter functions. Finally, we compare the results of numerical multiphase-flow simulations for the heterogeneous and upscaled fields.

UR - http://www.scopus.com/inward/record.url?scp=80051599835&partnerID=8YFLogxK

U2 - 10.1016/S0167-5648(04)80060-1

DO - 10.1016/S0167-5648(04)80060-1

M3 - Article

AN - SCOPUS:80051599835

VL - 55

SP - 313

EP - 324

JO - Developments in Water Science

JF - Developments in Water Science

SN - 0167-5648

IS - PART 1

ER -