Integrated Green Nanocomposite for Asphaltene Stabilization, Viscosity Reduction, and Sulfur Mitigation: Toward Sustainable Flow Assurance

Abstract The aggregation and precipitation of asphaltene along with viscous crude oils frequently constrain flow assurance. This work examines a multifunctional green nanoadditive based on Ni-doped CuO nanocomposite to control these issues at a minimal concentration. A series of experimental tests was systematically conducted to evaluate the performance of the nanocomposite, including modified asphaltene dispersion test (ADT), fluorescence microscopy, viscosity reduction at a fixed shear rate of 100 s-1, sulfur quantification via Energy dispersive X-ray fluorescence, and a H2S bottle. At a low dosage of 25 ppm, asphaltene was successfully stabilized, achieving inhibition efficiencies of 67-73% under high-salinity and high-viscosity conditions, while achieving 85% inhibition for up to five days in a viscous crude oil (API 22.7°). Rheological measurements showed that the viscosity dropped by about 37-40% at a temperature range of 20-60°C. Fluorescence microscopy further validated the results by showing improvements in asphaltene particle distribution and a reduction in aggregate size after treatment. Additionally, a strong affinity for sulfur-containing compounds was achieved after treating the oil, removing more than 40% of total sulfides and gaining about 90% of H2S elimination within one hour. This work proposes a single solution for eliminating several flow production challenges, eliminating the need for multiple chemicals to solve those issues, which supports the oil industry transition toward green and multifunctional nano chemicals.