Synthesis and Application of Viscosity Reduction and Pour Inhibition Systems for Deep Heavy Oil

Abstract

A targeted viscosity reduction and pour inhibition mixed system was developed to address the issues of high steam injection pressure, low thermal efficiency, and field incompatibility in deep heavy oil reservoirs. A pour inhibitor was synthesized from monomeric acrylic acid octadecyl ester and vinyl acetate, and a low-molecular weight viscosity reducer was synthesized from dopamine hydrochloride and methacryloyl chloride. The viscosity reduction and pour inhibition systems were constructed by compounding the pour inhibitor and viscosity reducer at different mass ratios. The viscosity reduction rate, pour inhibition performance, resistance of stability, mineralization, and temperature of the systems were tested and evaluated. The results showed that the viscosity reduction and pour inhibition systems exhibited high stability and a wide range of temperature and mineralization resistance. The system demonstrated viscosity reduction and pour inhibition effects in the mass concentration range of 2–10%, with the effectiveness increasing with higher concentration. At a concentration of 10%, the viscosity reduction rate reached 95.2% and the pour point decreased by 10.2 °C. Among them, the mixed system by compounding the pour inhibitor, viscosity reducer, and polyglycerol-10 caprylate in a mass ratio of 40:50:10 exhibited the best viscosity reduction and pour inhibition effects. Laboratory core flooding tests showed that the optimized mixed system had a recovery rate of 32.8% for heavy oil samples, significantly higher than that of traditional displacement methods such as water flooding, polymer flooding, and surfactant flooding. A field test was conducted, and the results demonstrated a significant increase in oil fluidity and oil production.