Numerical simulation of oil production using surfactant-polymer flooding

The paper is devoted to the numerical modeling of oil field development using enhanced oil recovery technologies based on surfactant-polymer flooding. The proposed approach is aimed at assessing the possible efficiency and advisability of using surfactant-polymer flooding at the later stages of real fields development. A computational scheme for modeling three-phase multicomponent fluid flow in heterogeneous porous media, taking into account the formation of an emulsion phase, as a result of binding water and oil due to surfactants influence, is described. This computational scheme is constructed similarly to the principle of the well-known IMPEC scheme and based on an implicit calculation of pressure by the finite element method and an explicit phase transfer between the cells of the finite element mesh at each time step. This makes it possible to calculate the effect of surfactants in each cell of the mesh independently of other cells. The scheme provides for the modeling of chemical reactions taking into account their rates and the amount of reactants in the mesh cells. The effect of enhanced oil recovery is achieved due to higher mobility and lower residual saturation of the emerging emulsion phase in comparison with the oil phase. Numerical experiments were carried out on a model of a real field with a large number of active wells and a highly heterogeneous porous medium. Three methods of field development are compared: water injection, polymer flooding, and injection of a surfactant-polymer solution. The convergence of the numerical scheme is shown for space and time mesh refinement. Compared to two-phase two-component flow, the additional computational costs associated with the formation of the emulsion phase and its subsequent flow do not exceed 10%.