Characterization of Three-Phase Flow in Porous Media using the Ensemble Kalman Filter

In this study, the ensemble Kalman filter is used to characterize three-phase flow in porous media through simultaneous estimation of three-phase relative permeabilities and capillary pressures from production data. Power-law models of relative permeability and capillary pressure curves are used and the associated unknown parameters are estimated by assimilating measured historical data. The estimation procedure is demonstrated on a twin numerical setup with two different scenarios, in which a synthetic 2D reservoir under three-phase flow is considered. In the first scenario, all the endpoints are assumed to be known and only the shape factors are estimated during the assimilation process. In the second, all the endpoints and shape factors are estimated by assimilating observed data. Accurate estimation of the unknown model parameters is obtained by assimilating oil, water, and gas production rates of the producers, and bottom hole pressure of the injector. Moreover, sensitivity analysis of the observations with respect to the parameters defining the relative permeabilities and capillary pressures shows that for the most sensitive parameters, better estimation and lower uncertainty are obtained at the end of the assimilation process.