Determination of Capillary Pressure and Relative Permeability From Spontaneous- Imbibition Data in Gas/Liquid/Rock

Abstract Capillary pressure and relative permeability are important parameters in reservoir engineering. Techniques frequently used to measure capillary pressure and relative permeability simultaneously are complicated and time-consuming. On the other hand, it is also difficult to measure the two parameters in low permeability rocks. It would be useful if capillary pressure and relative permeability could be inferred from spontaneous imbibition tests. This is because such tests are relatively simple, fast, and economical. In the present study, an analytical approach was developed to determine capillary pressure and relative permeability simultaneously by using experimental data of spontaneous water imbibition into gas- saturated rock. Spontaneous water imbibition tests in different rocks were conducted to test the proposed approach. Both capillary pressure and relative permeability were calculated using the proposed approach and the results were closely equal to those measured using different methods.