Characterization of lauryl betaine foam in the Hele-Shaw cell at high foam qualities (80%–98%)

Abstract

Lauryl betaine (LB) as an amphoteric surfactant carries both positive and negative charges and should be able to generate stable foam through electrostatic interaction with nanoparticles and co-surfactants. However, no previous attempts have been made to investigate the influence of nanoparticles and other co-surfactants on the stability and apparent viscosity of LB-stabilized foam. In this study, a thorough investigation on the influence of silicon dioxide (SiO2) nanoparticles, alpha olefin sulfonate (AOS) and sodium dodecyl sulfate (SDS), on foam stability and apparent viscosity was carried out. The experiments were conducted with the 2D Hele-Shaw cell at high foam qualities (80%–98%). Influence of AOS on the interaction between the LB foam and oil was also investigated. Results showed that the SiO2-LB foam apparent viscosity decreased with increasing surfactant concentration from 0.1 wt% to 0.3 wt%. 0.1 wt% SiO2 was the optimum concentration and increased the 0.1 wt% LB foam stability by 108.65% at 96% foam quality. In the presence of co-surfactants, the most stable foam, with the highest apparent viscosity, was generated by AOS/LB solution at a ratio of 9:1. The emulsified crude oil did not imbibe into AOS-LB foam lamellae. Instead, oil was redirected into the plateau borders where the accumulated oil drops delayed the rate of film thinning, bubble coalescence and coarsening.