Interface modification viscosity reducer for oil displacement as well as preparation method and application of interface modification viscosity reducer

The invention relates to an interfacial modification viscosity reducer for oil displacement as well as a preparation method and application of the interfacial modification viscosity reducer. The viscosity reducer comprises a terpolymer, and the terpolymer comprises a structural unit (I), a structural unit (II) and a structural unit (III) shown in the following formulas: R1 is selected from C2-C9 alkyl; r2 to R10 are independently selected from one of hydrogen, deuterium, fluorine, chlorine, bromine and C2-C9 alkyl groups, and m is 0, 1, 2, 3 or 4; and n is 0, 1, 2, 3 or 4. The preparation method disclosed by the invention comprises the step of enabling a reaction monomer to be in contact reaction with an initiator and a chain transfer agent in an organic solvent under a polymerization reaction condition. The interfacial modification viscosity reducer provided by the invention is applied to the field of heavy oil cold recovery/oil sand washing oil, and can effectively reduce the viscosity of heavy oil and impr