Validation of direct pore scale modeling approaches to wettability

by Raul Verma, Matteo Icardi, Masa Prodanovic
Manuscripts Year: 2015


Raul Verma, Matteo Icardi, Masa Prodanovic, Validation of direct pore scale modeling approaches to wettability, submitted March 2015​


Understanding of pore-scale physics  for multiphase  flow in porous media is essential for accurate description of various  flow phenomena.  In particular, capillarity and  wettability strongly  influence  capillary pressure-saturation and relative permeability relationships. Wettability is quantified  by the con- tact  angle of the fluid-fluid interface  at the pore walls.  In this work we com- pare the interface  capturing  method implemented  in a popular  open-source finite volume  computational fluid dynamics  solver  with a new formulation of the level set method that models capillarity-dominated flow and is less computationally expensive.  The methods  fundamentally differ in the way they  mesh porous  geometry  and capture  interfaces,  as well as in the num- ber of equations  solved  and other  implementation and algorithmic  details. Both methods  are able  to solve  curvature-driven flow and implement  arbi- trary  contact  angles  at  pore walls.   The methods  are tested  in rhomboidal packings  of spheres  for a  range  of contact  angles  and  for different  rhom- boidal configurations. Predictions are validated against  the semi-analytical solutions  obtained  by Mason and Morrow (1994).  We specifically focus on evaluating the accuracy of each method (algebraic VOF and level-set)  and benefits and limitations  of employing a less computationally intense method for semi-equilibrium  capillary-dominated flows vs.   the  full approximation of the Navier-Stokes  equation  applicable also to inertial  and viscous  flows. Consequences for larger  and more complex  problems  are also considered.




Validation of direct pore scale modeling approaches to wettability