The rheological properties of South China Sea (SCS) crude oil were studied.A group of synthetic long-chain polymers,including octadecyl acrylate-maleic anhydride bidodecyl amide copolymer (VR-D),octadecyl acrylate-maleic anhydride bioctadecyl amide copolymer (VR-O) and octadecyl acrylate-maleic anhydride phenly amide copolymer (VR-A),were employed to serve as viscosity reducers (VRs).Their performance was evaluated by both experimental and computational methodologies.The results suggest that the SCS crude oil has low wax content yet high resin and asphaltene contents,which lead to high viscosity through formation of association structures.Additionally,the SCS crude oil appears to be a pseudoplastic fluid showing linear shear stress-shear rate dependence at low temperature.Interestingly,it gradually evolves into a Newtonian fluid with exponential relationship between shear stress and shear rate at higher temperature.Synthetic VRs demonstrate desirable and effective performance on improvement of the rheological properties of SCS crude oil.Upon the introduction of 1000 ppm VR-O,which is synthesized by using octadecylamine in the aminolysis reaction,the viscosity of SCS crude oil is decreased by 44.2％ at 15 C and 40.2％ at 40 ℃.The computational study suggests significant energy level increase and shear stress decrease for VR-containing crude oil svstems.