Determination of Two-phase Relative Permeability from a Displacement with Safman-Rayleigh Instability Using a Coarse-Scale Model History Matching Approach

In heavy oil displacement by fluid injection, severe instability can occur due to the adverse mobility ratio, gravity segregation or compositional effects. However, when estimating relative permeability, most analytical methods assume a stable front in the displacement, which may be highly erroneous when used with unstable displacements. Quite often in such cases, history matching using a high-resolution model is preferred, however, it is computationally inefficient or impractical in some cases. This work describes a relatively fast methodology for estimating relative permeability from displacement with instability and compositional effect. It involves defining a set of 2-dimensional (2D) coarse-grid models and the tuning of a three-parameter correlation. By this approach, an attempt is made to resolve the fine-scale information without direct solution of the global fine-scale problem. The results of the coarse-grid history matching corrected by the proposed approach in this study showed that the improved methodology is three times faster, and required less than half the memory of a high-resolution 2D model.