Measurement of Three-Phase Relative Permeability with IFT Variation

Abstract

Abstract In this paper we present results of an experimental investigation of effects of variations in interfacial tension (IFT) on three-phase relative permeability. We report results that demonstrate the effect of low IFT between two of three phases on the three-phase relative permeabilities. In order to create three-phase systems in which IFT can be controlled systematically, we employed a quaternary liquid system composing of hexadecane (C16), n-butanol (NBA), water (H2O), and isopropanol (IPA). Measured equilibrium phase compositions and IFTs are reported. The reported phase behavior of the quaternary system shows that the H2O-rich phase should represent the gas phase, the NBA-rich phase to represent the oil phase, and the C16-rich phase to represent the aqueous phase. Therefore we employed oil-wet Teflon bead packs to simulate the fluid flow in a water-wet oil reservoir. We determined phase saturations and three-phase relative permeabilities from recovery and pressure drop data using the Welge method and the Johnson-Bossler-Naumann (JBN) method, respectively. The IFT range we studied was 0.03-2 mN/m. Measured three-phase relative permeabilities are reported. The experimental results indicate that the wetting phase relative permeability was not affected by IFT variation whereas the other two-phase relative permeabilities were clearly affected. As IFT decreases the "oil" and "gas" phases become more mobile at the same phase saturations. We obtained about a 10-fold increase in the oil and gas relative permeabilities against a i00-fold decrease in the IFT.