Filtrate reducer copolymer as well as preparation method and application thereof

The invention discloses a filtrate reducer copolymer as well as a preparation method and application thereof. The molecular structure contains a structural unit with a side chain containing an amide group, a structural unit with a side chain containing a sulfonic acid group, a structural unit with a side chain containing siloxane, a structural unit with a side chain containing ionic liquid and a structural unit with a side chain containing cyclic alkyl. The filtrate reducer copolymer is obtained through free radical polymerization of various alkenyl monomers in the presence of an initiator. The filtrate reducer copolymer can be firmly adsorbed on the surface of clay under a high-temperature condition, the salt resistance and calcium resistance of the filtrate reducer copolymer can be effectively improved by an ionic liquid chain segment in a molecular chain, and the temperature resistance of the filtrate reducer copolymer can be improved by an annular alkyl rigid structure. The synthesis method of the treatme