Effect of Temperature on Water-Oil Relative Permeabilities in Oil-Wet and Water-Wet Systems

Abstract

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Las Vegas, Nev., Sept. 30-Oct. 3, 1973. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgement of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract An apparatus has been constructed for laboratory measurement of water-oil relative permeabilities by the steady-state technique at elevated temperatures. Experiments were conducted on consolidated porous teflon and Berea sandstone cores with three oils: Kaydol, Protol and tetradecane having viscosities at room temperature of 130, 68 and 2 cp, respectively. For the oil-water systems, teflon was strongly oil wet and sandstone cores were water wet. Measurements were made under isothermal conditions at room temperature and were repeated at 200 degrees F for the teflon and 300 degrees F for the sandstone cores. Results of these measurements indicated that the effects of temperature on relative permeability curves were similar in both oil-wet and water-wet systems. At higher temperature, relative permeability to oil was found to be higher and residual oil saturation was lower. The rate of increase in relative permeability to water with increasing water saturation appeared to be higher at higher temperature. These effects seemed to be larger in systems with Kaydol and Protol than with tetradecane. Interpretations of results were made in light of fluids, fluid-fluid and fluids-solid properties. The changes in viscosity ratio with temperature appear to be a factor that influences relative permeability curves. Introduction The oil recovery mechanism involved in hot water flooding is generally believed to be the results of viscosity reduction and thermal expansion. The effect of lowering of the viscosity leads to a more efficient displacement. Test results have indicated that relative permeabilities to oil and to water, and the equilibrium saturations of residual oil and irreducible water also change due to an increase in temperature. Presently, the mechanism leading to these changes is not known. In the work on the effect of temperature on relative permeability of consolidated rocks, Weinbrandt and Ramey found that an increase in temperature from room temperature to 175 degrees F in Boise sandstone has caused the increase in irreducible water saturation, decrease in residual oil saturation and increase in the relative permeability to oil. Decrease in the relative permeability to water at saturations of below room-temperature residual oil but increase at flood-out were observed. By comparing their results to those of Owens and Archie, the latter dealing with the effect of wettability on relative permeability, Weinbrandt and Ramey suggested that the changes in relative permeability resulting from an increase in temperature may have been due to wettability changes.