Enhanced Oil Recovery using Carbonated Polymeric Nanofluids: A New Age Approach to CO2 Utilization and Corrosion Mitigation

Anthropogenic carbon emissions have become a global concern and several mitigation strategies have been tested. The utilization of carbon dioxide for enhanced oil recovery has the potential to support this cause, and carbonated water injection has gained popularity in recent times. However, this becomes detrimental as the metallic tubular serving as the conduit to the oil reservoir for CO₂ injection falls prey to severe side effects, such as induced corrosion. This study addresses this issue while suggesting a carbonated water formulation that can enhance oil recovery while reducing the corrosive effects of CO₂. Polymeric nanofluids (PNFs) were prepared with Polyacrylamide (PAM) in well-sonicated aqueous dispersions of Zinc Oxide nanoparticles (ZnO NPs). Two variants of ZnO NPs, one commercial (spherical morphology) and another in-house synthesized (flower-like morphology), were used at concentrations of 0.01 %, 0.02 %, and 0.03 wt%, and the resulting PNFs (named PCZ and PDZ, respectively) were analytically characterized and compared for efficacy in terms of CO₂ absorptivity, rheological behavior, interfacial tension (IFT) reducing ability, incremental recovery potential, and most importantly, corrosion inhibitory properties under carbonated conditions. It was discovered that the introduction of ZnO NPs at 0.01 wt% enhanced carbon dioxide absorption by 8.3 % (PCZ) and 26.88 % (PDZ), decreased interfacial tension from 40.54mN/m (0 wt%) to ∼14.67mN/m (PCZ) and ∼ 12.21mN/m (PDZ). At 0.03 wt% ZnO NP concentration, PCZ was able to reduce the corrosion rate by 58.68 %, and PDZ even performed better by reducing the rate to 70.67 %. In terms of incremental oil recovery through core flood tests, carbonated PDZ outperformed PCZ by 12–20 % of the original oil in place. Therefore, NPs in polymeric dispersions, if customized, can improve the oil recovery potential in the reservoir while carrying a higher amount of CO₂. In addition, the superior performance of the PDZ attests to the significance of the defined morphology, which plays a key role in the selection of NPs, because the flower-like morphology provides more sites for interaction with CO₂.