Calculation of Steam-water Relative Permeability Using Capillary Pressure Data

Various capillary pressure approaches such as the Purcell, Burdine, Corey, and Brooks-Corey methods were used to calculate steam-water relative permeabilities using the measured data of steamwater capillary pressure in both drainage and imbibition processes. The calculated results were compared to the experimental data of steam-water relative permeability measured in Berea sandstone. The steam-water relative permeability and capillary pressure were measured simultaneously. The differences between the Purcell model and the measured values were almost negligible for water phase relative permeability in both drainage and imbibition but not for the steam phase. The insignificance of the effect of tortuosity on the wetting phase was revealed. A physical model was developed to explain the insignificance of the tortuosity. Steam phase relative permeabilities calculated by other models were very close to the experimental values for drainage, but very different for imbibition, as expected. The same calculation was made for the nitrogen-water flow to confirm the observation in the steam-water flow. The results in this study showed that it would be possible and useful to calculate steam-water relative permeability using the capillary pressure method, especially for the drainage case.