The measurement of three-phase relative is often a difficult and time-consuming process. To this date only a handful of papers can be found in the literature on the measurement of three-phase relative permeabilities. Grader and O'Meara developed an unsteady-state technique for measuring three- phase relative permeabilities by extending the Buckley Leverett theory to three phases. The validity of this new unsteady-state technique has been verified recently for three immiscible liquids in a glass-bead pack with the help of a medical CT-scanner (Siddiqui and Siddiqui et al.) However, this new technique has not been applied to measure the three- phase permeabilities of a rock -fluid system similar to that of a typical petroleum reservoir. This present study focuses on the application of the extension of the Buckley-Leverett theory for measurement of three-phase relative permeabilities for a brine- oil-gas system in Berea sandstone cores (permeability range 100-400 md). Several experiments were conducted using a specially designed coreflooding unit in which pressure at six locations along the core and flow rates are recorded continuously with a computerized data acquisition system. The three-phase flowpath used for this study was dynamic gas injection into the cores having a different initial water and oil saturation each time. Three-phase relative permeability data derived this way were used in a simulator to predict the recovery curves. Results show a good agreement for the different cases studied. Comparison is also made between these data and the data from experiments done with three immiscible phases (Siddiqui).
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