Preparation of styrene-phenylamine monomer copolymer nanospheres and its performance for stabilizing CO2 foam

Abstract

Improving the stability of CO₂ foam is a core concern in CO₂ foam flooding oil recovery technology. Using hydrophobic nano-SiO₂ to enhance the stability of CO₂ foam is a common approach, but hydrophobic nano-SiO₂ faces challenges, such as easy aggregation, difficult dispersion, and performance needs to improve. In this article, a novel dispersion of styrene-phenylamine monomer copolymer (PSSN) nanosphere with primary amine groups on the surface was synthesized. The synthesis conditions of PSSN were optimized, and its performance for stabilizing CO₂ foam was evaluated. The experimental results demonstrated that PSSN had better performance for stabilizing CO₂ foam than that of hydrophobic nano-SiO₂ when using cocamidopropyl betaine (CAB) as the foaming agent. With the CAB concentration of 4000 mg/L and PSSN concentration of 100 mg/L in the brine having salinity of 8460 mg/L, the half-life of CO₂ foam at 90°C was 131 min, which was 43 min longer than that stabilized by hydrophobic nano-SiO₂ under the same conditions. This is for the first time that polystyrene microspheres with amine groups on the surface was used to stabilize CO₂ foam. The study provides a new nanoparticle option for stabilizing CO₂ foam.