Abstract: Disclosed are a polymer, a tackifier, a preparation method therefor and a drilling fluid. The polymer contains a structural unit represented by a formula (1), a structural unit represented by a formula (2) and a structural unit represented by a formula (3), wherein R1, R2, R3, R4, R5, R6, R7 and R8 are each independently hydrogen or C1 to C10 linear or branched alkyl; X is C1 to C10 linear or branched alkylene; Y is a formula (4) or C1 to C10 linear or branched alkylene; and M is hydrogen or an alkali metal, and A1, A2 and A3 are each independently a bond or C1 to C3 linear or branched alkylene. The polymer can still maintain excellent viscosity-increasing performance in a high-temperature and high-calcium environment.

Abstract: The present disclosure relates to the technical field of drilling, in particular to a composite material, a composition, a drilling fluid, and a method for plugging formation well wall fractures. The composite material includes a polymer matrix and metal ions embedded in the polymer matrix, an embedding rate of the metal ions is not less than 90 wt %, and turbidity of an aqueous solution of the composite material is not less than 1000 NTU under a condition of pH?8. The composite material can actively and quickly identify a change in a formation environment based on a difference in pH values between the drilling fluid and the formation environment, and achieve a precise response and precise matching with a formation well wall fracture environment, and a small amount of composite material can effectively increase a plugging rate of the formation well wall fracture.

Abstract: A dendritic polymer contains a dendritic polyester as a core, and a plurality of arms obtained by means of polymerization of an alkenyl monomer. The root-mean square radius of gyration of the dendritic polymer does not exceed 100 nm. The alkenyl monomer contains a non-ionic monomer and an anionic monomer. The polymeric segments formed by a monomer generally used for synthesizing a filtrate loss reducer are used as the arms of the dendritic polymer, which is obtained by means of free radical polymerization. Compared with a linear polymer having an identical molecular weight, the dendritic polymer has a smaller root-mean-square radius of gyration and is more compact in structure. suitable for use in a drilling fluid.

Abstract: A random copolymer, a preparation method of the random copolymer, a drilling fluid containing the random copolymer. The random copolymer contains structural unit (A) represented by formula (1), structural unit (B) represented by formula (2), structural unit (C) represented by formula (3), and structural unit (D) represented by formula (4) or (5): wherein X is halogen. When the random copolymer is used as a filter loss reducer in a high-calcium drilling fluid, the filter loss of the high-calcium drilling fluid can be reduced.

Abstract: A random copolymer, a preparation method of the random copolymer, a drilling fluid containing the random copolymer. The random copolymer contains structural unit (A) represented by formula (1), structural unit (B) represented by formula (2), structural unit (C) represented by formula (3), and structural unit (D) represented by formula (4) or (5): wherein X is halogen. When the random copolymer is used as a filter loss reducer in a high-calcium drilling fluid, the filter loss of the high-calcium drilling fluid can be reduced.