Preparation of SiO2-Fluorinated Acrylate Polymer Nanoemulsions (SCFs) and Their Application as Depressurization and Injection Treatment Agents

Abstract

For water injection development in low-permeability reservoirs, nanoscale SiO2-fluorinated acrylate polymer nanoemulsions (SCFs) with good properties were prepared through core–shell emulsion polymerization. The results show that nano-SiO2 particles are well dispersed, the average particle size of the SCFs is 113 nm, and the synergy among fluoride chain segments is good and effectively improves the utilization of fluorine atoms. SCFs form a low-surface-energy nanoscale hydrophobic film on the rock surface, which changes the original rock surface micro- or nanostructure, resulting in a water contact angle of up to 120° at the core. At 60 °C, the interfacial tension (IFT) between a 1500 mg/L SCF dispersion and white mineral oil is 1.86 mN/m, decreasing by 95.67% relative to the oil–water IFT at room temperature. The core flooding experiment shows that the depressurization rate reaches 29.62% in the 1500 mg/L SCF dispersion. Therefore, SCFs have broad application prospects in processes that eliminate water lock, reduce injection pressure, and increase injection volume.