Changes

==Capillary forces==

==Capillary forces==

Once a separate phase is formed, capillary forces become effective. Capillary forces arise at the interface between two phases across a restricted opening. [[Capillary pressure]] is a function of the interfacial tension between the immiscible fluids and the pore throat size. As the pressure difference across a capillary restriction increases, the interface deforms and eventually the nonwetting phase penetrates the restriction. Capillary effects only arise at the contact of two immiscible phases. Neither solution transport nor continuous phase is affected by capillary effects. The phase that preferentially wets the grain surfaces (usually water) is continuous. The nonwetting phase is generally assumed to form one or more continuous networks through a bed when its concentration exceeds between 4.5% and 17% of the pore volume.

Once a separate phase is formed, capillary forces become effective. Capillary forces arise at the interface between two phases across a restricted opening. [[Capillary pressure]] is a function of the interfacial tension between the immiscible fluids and the pore throat size. As the pressure difference across a capillary restriction increases, the interface deforms and eventually the nonwetting phase penetrates the restriction. Capillary effects only arise at the [[Fluid contacts|contact of two immiscible phases]]. Neither solution transport nor continuous phase is affected by capillary effects. The phase that preferentially wets the grain surfaces (usually water) is continuous. The nonwetting phase is generally assumed to form one or more continuous networks through a bed when its concentration exceeds between 4.5% and 17% of the pore volume.

==Capillary forces between small pores==

==Capillary forces between small pores==