Foam stabilized by SiO₂/AOS adsorbed at the gas–liquid interface: influence of the degree of nanoparticle modification

ABSTRACT

Foam fluids are thermodynamically unstable systems, and foam stability is the major problem that restricts the application of foam fluids in drilling, fracturing, and oil displacement. In this work, the controllable modification of the surfaces of nanoparticles was realized by adjusting the ratio of the silane coupling agent dimethyldimethoxysilane to SiO₂ nanoparticles, and the effect of SiO₂ modification degree on the foam static stability, bubble coarsening and liquid film viscoelasticity of the nanoparticle and surfactant compound foam system was studied. The experimental results showed that the effect of synergistic foam stabilization improved as the modification degree of nanoparticles and surfactants was increased. The best performance was observed when ω(SiO₂) was 2%, ω(AOS):ω(SiO₂) was 0.2, and the half-life of foaming liquid is increased to 79.7 min, which is about 10 times that of the non-compound system; SM-100 SiO₂/AOS foam has a minimum Ostwald ripening rate of 209075.1. The addition of highly modified nanoparticles could decelerate the coarsening rate of the foam, hinder the coalescence of bubbles, and enable the maintenance of good uniformity. In addition, the compound foam exhibited typical pseudoplasticity, SiO₂/AOS foam has the lowest flow behavior index of 0.4756, and the liquid film has large elasticity and strong energy storage, which makes the foam more stable. This research has enriched the research on the foam stabilization law of composite foam systems of nanoparticles and surfactants.

KEYWORDS:

• SiO₂ nanoparticles
• surface modification
• foam stability
• coarsening process
• Rheology

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (51674208), and the Opening Project of Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province (YQKF202010).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51674208]; Opening Project of Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province [YQKF202010].