Hello!
Kindly can someone let me that capillary pressure is continuous at the interface when flow is moving from low to high porous domain. Based on the capillary pressure's equation it should be discontinuous due to different porosity and permeability values.
Moreover, what boundary condition should I used to model this domain, especially the interface. I looked one B.C named as Porous Medium Discontinuity in Comsol but according to its theory flow is flowing from high permeable to low permeable domain. But, in my case it is opposite.
Thanks!
In reservoir models, the capillary pressure should be continuous across the interface, it will be a function of height above the free water level and fluid density difference whereas the phase saturations will be varying with rock quality under static conditions. Boundary conditions are normally no flow on the perimeter or an aquifer function with sources and sinks at wells.
Nice question, if you’re doing an imbitition simulation in a medium with a sharp increase In permeability and initially 100% Saturated by a non-wetting phase, I think the capillary pressure will be discontinuous at the location of this sharp change and an accumulation of the wetting phase will take place until a sufficient reduction of capillary is reached, so that the Wetting phase can continue flowing across the sharp permeability interface.
For a deeper explanation, I recommend to read works from Bill Rossen (TUDelft) related with Foam generation across sharp permeability transitions.