The centrifuge method for two-phase relative permeability measurements has been extended for use with three mobile phases. The oil and water production obtained from a sample rotated in an air-filled sample holder straightforwardly yields the three-phase oil and water (drainage) relative permeabilities along a trajectory in the saturation ternary diagram.
The criteria for reliable measurements are discussed. It is shown that these experimental requirements are similar to those for the two-phase case.
The extended centrifuge technique has been used for measuring the three-phase oil and water relative permeabilities on Weeks Island and Berea samples. The results of these experiments show that the shape of the oil isoperms in the saturation ternary diagram is concave when viewed from the oil apex. This shape implies a more favourable recovery for immiscible gas (CO2) injection into the Weeks Island B Sand than predicted on the basis of the convex oil isoperms calculated with the models of Stone or Hirasaki.