An analytical water relative model based on the theory of coupled electricity-seepage and capillary bundle pore
structure is described. The model shows that the relative permeability of water is affected by two kinds of parameters,
which are depicted as static parameters and dynamic parameters. Revised Kozeny-Carman equation and Archie formulas
are introduced to deduce the model, which enhance the characterization ability of pore structure. Two displacing states,
where we summarized that oil coats capillary walls and oil occupies capillary centers are also discussed for optimization
of the model. In contrast to existing empirical formulas where relative permeability is strongly related to capillary pressure
and fractal dimension, we introduce only water saturation and saturation index as input parameters, which make the
model simpler to use. Petrophysics and unsteady relative permeability experiments (oil displacing water) are carried out to
testify the two models. The fitting results show that for oil displacing experiments presented in this paper, the displacing
state where oil coats capillary walls is suitable to predict the relative permeability of water.
Effect of hydrogel particle additives on water-accessible pore structure of sandy soils: A custom pressure plate apparatus and capillary bundle model
