High temperature resistant oil-soluble viscosity reducer and preparation method thereof

The present invention discloses a high temperature resistant oil-soluble viscosity reducer and a preparation method thereof, and belongs to the technical field of petroleum exploration. The high temperature resistant oil-soluble viscosity reducer comprises, by weight, 2-4% of an ethylene-vinyl acetate copolymer, 1-3% of fatty amine polyoxypropylene polyoxyethylene ether, and 93-97% of solvent oil. The preparation method comprises: adding an ethylene-vinyl acetate copolymer to solvent oil, stirring for 3-5 h at a temperature of 45-55 DEG C to completely dissolve the ethylene-vinyl acetate copolymer, heating fatty amine polyoxypropylene polyoxyethylene ether to a temperature of 45-55 DEG C, mixing the heated fatty amine polyoxypropylene polyoxyethylene ether and the obtained substance, and continuously stirring for 3-5 h at a temperature of 45-55 DEG C so as to obtain the finished product. According to the present invention, the viscosity reducer resists the high temperature of 350 DEG C, is suitable for heavy oil thermal recovery huff-puff, is not affected by the crude oil nature and the water content, and has good viscosity reducing performance; and with the matching with the steam huff-puff, the viscosity reducer is applied on the heavy oil thermal recovery well, such that the steam injection pressure can be reduced, the steam wave and the volume can be expanded, the crude oil fluidity can be improved, and the oil well oil yield and the gas-oil ratio can be improved.