This document is an expanded abstract.
Summary
Many physical factors are affecting relative permeability. These factors could be wettability, interfacial tension, and pore size distribution of the porous media. All these factors significantly change the shape of the relative permeability curve. The change of interfacial tension of flowing phases can considerably change flow characteristics especially in gas condensate reservoir or gas injection into wells with near miscible conditions.
Assuming that physical core properties and experiment conditions are constant, interfacial tension as the only variable would change relative permeabilities. Here our objective is to estimate relative permeability at lower interfacial tensions from immiscible relative permeability. We will also estimate the change of residual oil saturation with interfacial tensions.
In this paper, we have implemented Michaelis Menten Kinetics model to evaluate residual oil as a function of interfacial tension. Also, a new set of correlations was purposed to calculate gas and oil relative permeability at different IFT. The accuracy of the model is then assessed against experimental data available in literature and predictions of a default model in commercial simulators (Coat’s model). Although the model needs fewer input data and it requires fewer calculations than Coat’s model, it improved predictions.
Introduction
The effect of interfacial tension on oil recovery is well documented in the literature. In this paper, we will focus on modelling change of residual oil saturation to gas (Sorg) and two-phase gas/oil relative permeability with interfacial tension (IFT).
Longeron (1980) examined the effect of IFT values on two-phase gas/oil relative permeability and residual oil saturation at high pressure and temperature. Interfacial tension between oil and gas was controlled by pressure and pre-equilibrated fluids (methanol/n-heptane) before each coreflood. They performed corefloods with IFTs ranging from 0.001 to 12.6 mN/m. They concluded that there is a relationship between IFT values and relative permeability and residual oil saturation. Below a critical IFT value of 0.04mN/m, the effect was more pronounced.
