Synthesis of biological nanocomposite fluids and enhanced crude oil recovery

Aiming at the problems of small pores, complex structure, large seepage resistance, and poor recovery effect in the development process of offshore medium and low permeability reservoirs, a green and environmental friendly biological nanocomposite fluid (BNF) was developed to enhanced crude oil recovery (EOR). Fe 3 O 4 @SiO 2 -Ag nanoparticles (NPs) were synthesized in the laboratory, and citric acid, tannic acid, sodium alginate, and trehalose lipids were used as surface modifiers for NPs and as fluid stabilizers. The nanocomposites were characterized by SEM–EDS, TEM, FTIR, XPS, XRD, and VSM. The EOR mechanism of BNF was studied by laboratory experiments, in which the interfacial tension can be reduced by 80 %. Moreover, 500 ppm BNF could keep oil and water emulsified for more than 3 months. Static separation of oil droplets and dynamic stripping of oil film exhibited obvious effects, and the bioactive substances’ dispersant and NPs can jointly drive away residual oil. The experiment on core displacement of crude oil showed that 500 ppm BNF can enhance oil recovery by 15.56 % on the basis of water flooding. The BNF oil displacement agent is economic and environmental friendly, providing a new method for the green and high-quality development of offshore oil fields.