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A one-dimensional ternary two-phase simulator has been extended to include improved physical properties. These physical properties -such as phase behavior, interfacial tension, residual saturations, relative permeabilities, phase viscosities, wettability, capillary pressure, adsorption and dispersion -are modeled as concentration dependent functions. Their functionality completely controls the chemical flood transport phenomena.In this paper, the influence of phase behavior, interfacial tension reduction, mobility control and wettability alteration on chemical flooding are analyzed. In a subsequent paper the influence of capillary pressure, adsorption, and physical and numerical dispersion will be presented. The main application of the simulator here presented is to describe enhanced oil recovery processes. It may also be applied to describe oil spill cleaning and groundwater contamination.

This is the second of two joint papers which study the influence of several physical properties on the transport phenomena in chemical flooding. To that aim, we use a previously reported ternary two-phase model into which representative physical properties have been incorporated as concentration-dependent functions. Physical properties such as phase behavior, interfacial tensions, residual saturations, relative permeabilities, phase viscosities and wettability have been analyzed in the first paper.In this paper, we discuss the influence of capillary pressure, adsorption of the chemical component onto the rock and dispersion. Although arising from different phenomenological sources, these transport mechanisms show some similar effects on concentration profiles and on oil recovery. They are studied for systems with different phase behavior. A numerical analysis is also presented in order to determine the relevance of the number of grid blocks taken in the discretization of the differential equations. This numerical analysis provides useful guidelines for the selection of the appropriate numerical grid in each type of displacement.

A chemical flood simulator of a three-component, two phase system has been extended to include concentration dependent functions: phase behavior, relative permeabilities, capillary pressure, interfacial tension, residual saturations, phase viscosities, wettability etc. Their influence on concentration profiles and on oil recovery is analyzed here upon. Introduction The application of the multicomponent, multiphase flow theory to chemical flooding has been superbly presented by Lake et al, Winter et al, Helfferich and Hirasaki. Those studies lead to the building of more and more complex simulators which have culminated with UTCHEM of Pope et al UTCHEM with 19 components and 4 phases has incorporated most physical phenomena. For a Surfactant Pilot Simulation, those physical phenomena were described in terms of more than 70 parameters. Therefore, the simulation has to be run on a Cray computer. Our aim is to contribute to a better understanding of the chemical flood transport phenomena using a simple model. This model is represented by a system nonlinear differential equation: the continuity equation for the transport of the components and Darcy's equation for the two-phase flow. The system of equations is completed with the equations of state describing the mass transfer of the three components between the two phases. In fact, the phase behavior of the chemical-oil-water components controls all the chemical flood transport phenomena. Phase behavior is described by a modification Larson's model to consider the dependence of the solubilization and swelling parameters on chemical concentration. In turn, interfacial tension reduction depends on phase behavior. Residual phase saturations are functions of the interfacial tension through the capillary desaturation curve. This curve, consequently influences relative permeabilities, capillary pressure and wettabilities. On the other hand, chemical concentration changes phase viscosities, adsorption and dispersion. Those complex and coupled physical properties and transport phenomena are taken into account. Their effects on concentration profiles and on oil recovery are analyzed considering the injection of an aqueous phase constant composition chemical slug followed by a continuous bank of water. This model is solved by an iterative finite-difference procedure that allows implicit calculation of pressures and Darcy's velocities and explicit calculation of concentrations. It is run on a PC 486 computer. Model Description Assumptions. The model assumes that the flow is isothermal, one-dimensional and incompressible, the porous medium is uniform and isotropic, cross-sectional area, porosity and absolute permeability are constant. Two mobile phases (aqueous and oleic) and three components (water, petroleum and chemical) are considered. There is no volume change with the mixture of the components in each phase. The system is in local thermodynamic (phase) equilibrium. Darcy's law applies and its gravity driven flow term is neglected. Flow Equations and Solution Technique. The continuity equation for the transport of each component and Darcy's equation for the flow of both aqueous and oleic phases are applied taking into account the above assumptions. The set of differential equations thus obtained, as well as their numerical solution, was presented in detail in a previous work. Initial and Boundary Conditions. Initially the porous medium contains oil at its waterflood residual oleic phase saturation Sorh and there is no chemical component. At inlet overall concentrations and flow rates are specified. The injection of an aqueous phase constant composition chemical slug followed by a continuous bank of water is considered. The slug size, tDs, is 0.2 PV. Physical Property Relationships Phase Behavior Model. Numerical representation of phase diagrams is accomplished following Larson.