Study on the influence of SARA fraction in heavy oil on the oil recovery during water flooding by experiments and the molecular dynamics simulation

W/O emulsification in the J-7 reservoir has been regarded as the main reason for enhancing oil recovery. Therefore, in this article, the chemical structures of SARA fractions of JD-1 crude oil were obtained through characterization experiments, and the effect of the influence of SARA fractions on the W/O emulsification and the oil recovery by using emulsification experiments, interfacial experiments, emulsification experiments, and water flooding experiments. Results showed from emulsification experiments that the emulsification degree of the simulated oil containing asphaltenes was higher than other simulated oils. All emulsions of SARA fractions after emulsifying were W/O emulsions, but compared with other components, the performance of emulsions of asphaltenes was the best. The viscosity of emulsions reached 8.16–18.38 times that of simulated oil, the average size of was only 0.68 μm, and the stability was also very good. From interface tension and expansion modulus experiments, it can be seen that after adding asphaltenes, the decrease degree of interface tension and the increased degree of expansion modulus were the most. The result of molecules dynamic simulations showed that the adsorption force on the oil-water interface of asphaltenes was greater than other components. The water flooding experiments found the recovery of the simulated oil containing asphaltenes reached 43.81%, which was higher than other simulated oil, indicating that the easier W/O emulsification was formed, the recovery rate was higher.</p

Additional file 1 of Mackinawite nanozymes as reactive oxygen species scavengers for acute kidney injury alleviation

Additional file 1: Figure S1. The release trend of hydrogen polysulfide from GFeSNs. Figure S2. Iron ions released from different concentrations of GFeSNs in PBS solution. Figure S3. AFM image of GFeSNs and the corresponding height analysis. Figure S4. •OH scavenging ratio of the GFeSNs. Figure S5. O2•− scavenging efficiency and •OH scavenging ratio of GSH. Figure S6. O2•− scavenging efficiency of GFeSNs after 24 h and 48 h in PBS. Figure S7. CAT-like activity of GFeSNs. Figure S8. Different enzyme-like activity of GFeSNs under different pH conditions. Figure S9. SEM of GFeSNs after dispersed in distilled water for 24 h, 48 h, and 96 h, respectively. Figure S10. In vitro hemolysis test of GFeSNs. Figure S11. In vivo toxicity evaluation of GFeSNs to major organs (heart, liver, spleen, lung, and kidney) 7 days and 30 days after intravenous administration. Figure S12. Serum biochemistry assay and complete blood panel data of mice intravenously injected with PBS or GFeSNs at 24 h