A Study On The Mechanism Of Polymer-enhanced Foam Based On Molecular Dynamics Simulation

Stable foam is very important to improve oil recovery in oil field.Complex formation conditions make foam unstable in oil layer and the application effect of foam flooding is not satisfactory.Adding Polymer to foam is a way to enhance foam Stability.In this paper,the mechanism of polymer enhancing foam stability is studied,and the idea of how to use polymer to enhance the stability of foam is provided in order to improve the service effect of foam flooding and enhance the recovery of crude oil.In this study,experiments and molecular dynamics simulations are combined to explain the macroscopic phenomena in experiments from a microscopic perspective by means of molecular dynamics simulation.The difference of common foam stability is mainly caused by the interaction of surfactant molecules on water molecules and the arrangement of surfactant molecules on the surface of foam film.Polymers do not always enhance foam stability,and its effect on foam stability depends on the electrical properties of surfactants and polymers.When they have same electrical properties,the repulsion between them and the viscosity enhancement of polymer have the opposite effect on foam stability,so polymers can strengthen the stability of foam only under certain conditions.The stability of foam is divided into two stages: liquid film drainage and liquid film rupture,and when polymer is added,the foam liquid film is more prone to rupture.N-pentane can enhance the stability of foam,while n-octane,n-dodecane and n-hexadecane make foam stability worse,in which n-octane has the greatest damage to the stability of common foam,and when polymer is added,the tolerance of foam to n-dodecane becomes worse and that of n-octane was better.