Comb type polymer emulsion applied to drilling fluid and preparation method of comb type polymer emulsion

The invention relates to a comb type polymer emulsion applied to drilling fluid in a drilling process. The comb type polymer emulsion is mainly used for improving viscosity and reducing filtration loss. The type of the comb type polymer emulsion is water-in-oil type; the comb type polymer emulsion is high in content of polymer; the content of the polymer in the emulsion is larger than 50%; the emulsion is low in dosage; the effective dosage of the emulsion in the drilling fluid is smaller than 0.5%; the comb type polymer emulsion is simple in preparation process; compared with other polymer powder, the polymer emulsion is low in preparation cost, simple to use, can be directly poured into a drilling fluid circulation system and does not need to be used after an adhesive solution is prepared. The comb type polymer is characterized in that the rigidity of a molecular chain is enhanced by introducing large side groups; the resistance to temperature and salt of the polymer is improved; compared with the existing drilling fluid polymer, the molecular chain is not liable to break; the polymer is high in viscosity retaining rate and can be applied to the drilling fluid in relatively strict and complex stratum; the performance of the drilling fluid is improved.