Impact of Three-phase Relative Permeability Model on Recovery in Mixed Media – Miscibility, IFT and Hysteresis Issues

The most widely used three-phase relative permeability models are Stone1 and Baker. Two advanced models have been developed more recently (Blunt, 1999; Jerauld, 1997). The mixed-wet condition is perhaps the most frequently encountered wetting condition worldwide. Blunt’s model is complex to employ in simulators in contrast with the relative ease of use of Jerauld’s model. An advantage of Jerauld’s model is that it incorporates the effect of IFT between phase pairs. The ability to model mixed wettability and to incorporate IFT makes this an attractive option to investigate recovery in mixed wet reservoirs. In this paper Stone1 and Jerauld’s models are compared. We illustrate the differences in performance prediction between these two models in three-phase kro for the same two-phase relative permeability data sets. Then we show how these two formulations can be cast on one another to be able to use them in commercial simulators. Recovery prediction differences as well as the effect of gas miscibility on krow are shown here. Analysis of hysteresis in mixed-wet system reveals that it has less effect on recovery in comparison with water-wet systems and it does have much less effect than wettability.