There are various interface phenomena in the process of foam flooding, so the interfacial rheological technique has a broad application prospect in the field of foam flooding. We can obtain the micro process information of interface through the study of interfacial rheological properties, which contributes to obtain a better explanation of the mechanism of foam generation, foam stability, and the effect of foam flooding. In this paper, the interfacial dilational rheological technology was used to investigate surface rheological properties of foam flooding systems. At the same time, the relationship between interfacial rheology and foam flooding recovery was also studied. To study the relationship between foam performance and surface parameters, sodium dodecyl sulfate (SDS)/long chain alcohol systems and long chain alkyl three methyl ammonium chloride systems were investigated.

Results show that due to different matchings of long chain alcohol molecules and SDS molecules, foaming volume and foam half-life of SDS solution increase at first then decrease with addition of lauryl alcohol, myristyl alcohol, cetyl alcohol and stearyl alcohol. Results show very slight variations in surface tension, while dilational modulus, elastic modulus, and surface viscosity of the systems increase at first then decrease. With the growth of hydrophobic chain, foaming volume and foam half-life of LTAC, TTAC, CTAC and OTAC decrease in turn, surface tension shows subtle changes, dilational modulus and elastic modulus decrease in turn. However, we obtain relatively low value for the viscous modulus of all the four long chain alkyl three methyl ammonium chloride systems. Foaming ability of foam flooding systems is controlled by surface viscoelasticity. Stability of foam flooding systems is mainly affected by surface rheological properties, and there is significant linear relationship between foam half-life and elastic modulus. Combining with the displacement experiment, a greater interfacial dilational elasticity results in a higher oil recovery. The conclusion is consistent with results of injection pressure in the macro core-flooding experiment and the change of sweep efficiency in the microscopic displacement experiment.

The results will provide insights in understanding the mechanism of foam flooding from the point of interfacial rheology.

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