Search

The most popular oil displacement technique in oilfield development is water flooding, yet sustained water flooding makes it simple to create water channeling in the formation, lowering development efficiency. A high strength agar was synthesized by using raw agar and 3-chloro-2-hydroxy-propyl trimethyl ammonium chloride, and it was then combined with PAM to prepare a plugging system to address the issue of water channeling in old oilfields. The successful synthesis of a modified agar was demonstrated by FITR, EM, TG/DSC, and its temperature resistance and agar strength were improved. Gelation and flow experiments were used to test the gelation and plugging characteristics of the plugging system. The results show that the plugging system is a pseudoplastic fluid, the temperature resistance less than 120 °C, the salinity resistance less than 1 × 105 mg/L, the gelation time of is 1 ∼ 3d, the gelation strength reaches grade I, the resistance coefficient less than 10, the breakthrough pressure gradient greater than 20 MPa·m−1, the plugging ratio greater than 90%, and the oil recovery ratio increases 22.8%. This work's study has a significant impact on enhancing oil recovery. [ABSTRACT FROM AUTHOR]

AbstractW/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. [ABSTRACT FROM AUTHOR]

AbstractWater flooding reservoirs are susceptible to a number of challenges, including an increase in reservoir heterogeneity and an elevated water content over the course of production. This can significantly diminish crude oil recovery efficiency. In order to address the issue of low water flooding recovery efficiency, a new approach to synthesizing an amphiphilic Janus TiO2 nanoparticle is presented. The Pickering emulsion method, utilizing sucrose stearate (SE-15) as the dispersant, allows the construction of an in-situ emulsified nanofluid (Janus TiO2/SE-15) with a water-in-oil (W/O) type morphology. Zeta potential experiments revealed that the nanofluid exhibited optimal stability when the mass fraction ratio of SE-15 to Janus TiO2 was 2:3. The nanofluid performance study demonstrated that the water-wet contact angle of the core could be reduced from 100° to 88.5° after 2 h of immersion. Moreover, the formation of a water-in-oil emulsion was observed between Janus TiO2/SE-15 and crude oil, with the emulsification viscosity enhancement rate exhibiting the greatest increase at the concentration of Janus TiO2/SE-15 of 0.08%. The results of core drive experiments indicate that the nanofluid drive can effectively increase the injection pressure and expand the wave volume. The results of core drive experiments indicate that nano-fluid drive can effectively increase the injection pressure and expand the wave volume. The final recovery rate of Janus TiO2/SE-15 nano-fluid was 61.77%. The Janus TiO2/SE-15 nanofluid, the subject of this study, is of significant importance for water flooding reservoirs, as it can be employed to enhance recovery. [ABSTRACT FROM AUTHOR]