1. A computing system implemented method comprising: receiving, in a computing system, fluid saturation data for fluid saturation parameters associated with permeabilities of a multidimensional spatial model of a geologic environment wherein the multidimensional spatial model comprises a grid cell model that comprises a plurality of grid cells; identifying, using the computing system, grid cells of the grid cell model that violate at least one criterion that depends on at least two different fluid saturation parameters; adjusting, using the computing system, at least a portion of the fluid saturation data for at least a portion of the identified grid cells to provide adjusted fluid saturation data by optimizing a quadratic function of different fluid saturation parameters subject to linear constraints wherein at least one of the linear constraints depends on at least two different fluid saturation parameters; and simulating, using the computing system, flow of fluid using the adjusted fluid saturation data for fluid saturation parameters associated with permeabilities and the multidimensional spatial model of the geologic environment.