(400i) Effect of Spacer Nature on Foaming Properties of Cationic Gemini Surfactant

Surfactants are widely used in the Enhanced Oil Recovery processes. Gemini surfactants are a special type of surfactants containing more than one hydrophilic head group and hydrophobic tail group. Macroscopic sweep efficiency can be increased by the formation of stable foam in EOR processes. This paper reports the foaming properties of two newly synthesized cationic gemini surfactants with different spacer nature.

The foaming properties of a novel cationic gemini surfactant were measured using a Dynamic Foam Analyzer which is based on the idea of optical measurements. This device allowed us to find the foam formation, the foam stability, and bubble count, etc. The foam was generated by blowing gas at a flow rate of 0.2 L/min through a Porous Media. This was located at the bottom of a glass tube where 50 mL of the aqueous surfactant solution was placed. The foam was allowed to build up for 5 seconds. Then, the bubbling was stopped, and the evolution of the foam was monitored.

Both surfactants showed excellent thermal stability in seawater and no precipitation was observed. Bubble count, average bubble radius, foam height, foam liquid stability, and foam volume stability were measured in the glass column by means of an optical sensor. The foaming properties of the gemini surfactants were superior compared to the foaming properties of commercially available cationic and anionic surfactants. In addition, we found that the counterion also affects the foaming properties significantly. Results showed that the novel gemini surfactant with a benzene ring and chlorine counterion gives better results as compared to a benzene ring and bromine counterion.

This work reports two newly synthesized cationic gemini surfactants for EOR in carbonate reservoirs. It shows the impact of counterion on foaming properties and hence enhances the understanding of tuning the structure of the surfactant to improve foam stability.