Mechanism study of nano-laponite modified by low molecular alkylamine to reinforce the stability of high-temperature foam

Abstract

The stability of high-temperature foam is crucial to mobility control in steam injection for enhanced heavy oil recovery. In this study, nano-laponite was modified by low molecular alkylamine with different chain lengths to reinforce the stability of high-temperature foam. It is found that the addition of nano-laponite modified by n-hexylamine can greatly improve the foam stability under high temperature conditions. There is an optimal concentration of n-hexylamine for the modification of nano-laponite to ensure the foam stability reaches the highest. The zeta potential and contact angle measurements indicate that hydrophilic nano-laponite can be changed to intermediate hydrophobic and causing slightly aggregation of the modified nano-laponite, which results in significant increase of bulk viscosity and interfacial dilational modulus. The laser-induced confocal microscopy observations confirm that the modified nano-laponite with optimal hydrophobicity adsorbed at the gas-liquid interface can greatly increase the mechanical rigidity of the liquid film to inhibit the bubbles coalescence and disproportionation. Moreover, the modified nano-laponite formed a three-dimensional network structure between the bubbles can increase the viscosity and structural strength of liquid film to slow down the liquid drainage and bubbles coalescence, and thus significantly improving the foam stability under high temperature conditions.