Application of constrained variable metric method to the inverse parameter estimation of capillary pressure, saturation, and relative permeability relationships

摘要

Constitutive relationships for the capillary pressure, saturation, and relative permeability controlling oil-water-air multiphase flow have been given. Relatively permeability outflow experiments of two-phase fluid on clays soil samples were conducted in laboratory. The optimal estimation values are obtained by adopting constrained variable metric method to inverse the model parameters. Five different initial parameters were chosen to examine the solution convergence, and it was shown that initial parameter estimates do not influence the results of the parameter estimation. Results show that the optimized values by the numerical method is in good agreement with the experimental data, and the comparison analysis validates the reliability and practicability of numerical model. It provides sufficient information to successfully apply the parameter estimation approach.