Fabricating a heavy oil viscosity reducer with weak interaction effect: Synthesis and viscosity reduction mechanism

We synthesized a copolymer with strong hydrophilicity and low surface and interfacial activity, which reduced the viscosity of heavy oil by interacting with asphaltenes or resins via hydrogen bonding. Water-soluble terpolymers (PAMD) were synthesized by the copolymerization of acryloyl morpholine, maleic anhydride with N, N-dimethylacrylamide in pure water. The copolymer showed low surface and interfacial activity, as well as the ability to weakly interact with heavy oil to form oil-in-water emulsions under stirring, but reducing the viscosity of the heavy oil by more than 90%. Under the condition of weak interaction between polymer and heavy oil, the oil-in-water emulsions dehydrated within 1 h to form oil and aqueous phases, which could be reused for the viscosity reduction at least five times. Therefore, this novel heavy oil viscosity reducer to provide a convenient and effective technique for oil extraction and reduce the burden of economic costs.