Estimation of Relative Permeability Parameters in Reservoir Engineering Applications

In a reservoir application, there are a large number of parameters that can be considered for estimation during history matching of the simulated model to the production data. If traditionally, parameters like porosity and absolute permeability have been most often included in such applications, this study focuses on researching the possibility of estimating the relative permeability curves in an assisted procedure by means of the Ensemble Kalman filter (EnKF). Stand alone estimation of the relative permeability parameters, as given by the Corey parametrization, as well as combined absolute permeability - relative permeability estimation experiments were performed on a synthetic study case and the ability of the EnKF to recover the true values of the parameters, given bottom-hole injector pressure and oil/water producer rates measurements, was tested. The influence of the initial distribution of the relative permeability parameters on the value of the estimates and the reduction of uncertainty, as well as that of the number of the measurements and the length of the assimilation period, in terms of covering or not the water breakthrough moment, were also investigated. Results show that some of the relative permeability parameters (the Corey oil coe±cient) can be recovered from the measurements, while others (the relative permeability end points) are not very sensitive to data assimilation and that estimating relative permeability has a positive e®ect on the estimation of absolute permeability, at the loss of accuracy of the relative permeability parameters estimations.Applied mathematicsElectrical Engineering, Mathematics and Computer Scienc