Talk:Buckley–Leverett equation

Relative Permeability as a function of saturation
Web articles on the the Buckley-Leverett equation point out that it assumptions imply that the "relative permeabilities" of oil and water become a function of the "saturation of water" alone. This leads to an equation whose unknown function is S, which is the saturation of water. But to solve the equation, I have seen no discussion of exactly what functions the "relative permeabilities" are of S, or any statement about whether solving the equation depends on knowing these functions explicitly. This article could made a contribution by clearing up this point.