An apparatus for the determination of relative permeability under simulated reservoir conditions has been designed, constructed, and operated successfully. Complete water-oil relative-permeability data, with kerosene and simulated reservoir brine have been taken on four natural-sandstone cores at fluid pressures to 5,000 1b./sq. in. and overburden pressures to 10,000 1b./sq. in. One run was made at low pressure at a temperature of 160°F. for comparison with the results at low temperature. The apparatus is now being expanded so that gas-oil relative-permeability data may be taken, and crude oil containing gas in solution may be employed as the oil phase.

The results indicate that essentially the same water-oil relative-permeability data are obtained at fluid pressures of 5,000 1b./sq. in. as at 30 1b./sq. in. gauge. The application of overburden pressure causes a reduction in both water and oil effective permeability in about the same proportion as it affects the single-phase permeability. Consequently the calculated relative permeabilities are affected to only a moderate extent. The results of the one run at 160°F. were in good agreement with the values obtained at room temperature.