Dynamic covalent bond cross-linked oil displacement polymer and preparation method thereof

Abstract

The invention relates to a dynamic covalent bond cross-linked oil displacement polymer and a preparation method thereof. According to the invention, acrylamide is used as a main monomer to increase the length of molecular chains, so that the frictional resistance between the molecular chains is increased to improve the viscosity of a solution, diacetone acrylamide is used as a functional monomer to copolymerize with acrylamide to introduce keto-carbonyl into a polymer chain to realize crosslinking with adipic dihydrazide, and thus the nonionic polymer cross-linked by the dynamic acylhydrazone bonds is obtained. The polymer chain does not have ions, so that charge shielding and flocculation effects of various salt ions are avoided, and relatively high viscosity can be kept in hypersalinity water. The polymer takes an acylhydrazone bond which can be dynamically formed and dissociated as a chemical crosslinking point, and the acylhydrazone bond is used as a stimulus-responsive dynamic chemical bond, so that the reversibility of physical crosslinking is maintained, the strength of chemical crosslinking is also realized, and reversible formation and fracture can be realized under the stimulation of an external environment so as to overcome the defect of poor shear resistance of a traditional polymer.

Description

technical field [0001] The invention relates to a dynamic covalent bond cross-linked oil-displacement polymer and a preparation method thereof, belonging to the technical fields of oil exploitation, transportation and chemical industry. Background technique [0002] Petroleum is the lifeblood of economic development, and my country's dependence on foreign oil is as high as 72%. At present, many water flooding oilfields in China have entered the middle and late stages. Due to the heterogeneity of reservoirs and unfavorable mobility ratio in this period, there is still a large amount of remaining oil in the formation after water flooding, and the water injection recovery rate is less than 40%. %, the water cut of the reservoir is generally above 95%, and the problem of viscous fingering and tongue entry is serious, which generally manifests as high water cut in oil wells, low production, and poor economic benefits of exploitation. Due to the contradiction between requirements...

AI Technical Summary

Problems solved by technology

However, the diameter of sand particles in high-porosity and low-permeability reservoirs is generally less than 60 μm, and the diameter of pores is generally less than 10 μm. -5 μm, the pore diameter of the microcapillary pores is less than 0.2 μm, the fracture width is less than 0.1 μm, and the median particle size of the oil displacement agent after swelling is above 761 μm, so it is not suitable for medium and low permeability reservoirs, and it is polymerized step by step The polymetallic heteropolyacid salt-polyol initiation system with molybdenum has high requirements on industrialization level

[0004] Chinese patent document CN101775275A discloses a new viscoelastic particle oil displacement agent and its preparation method. The new viscoelastic particle oil displacement agent introduces a branched structure on the basis of traditional polyacrylamide to form a small amount of crosslinking points, but due to The irreversibility of crosslinking, its salt resistance, shear resistance and viscosity increasing effect are poor

[0005] Chinese patent document CN112195020A discloses a dynamic nano-glue system and a water control method for enhancing oil recovery. Viscosity has great uncertainty and is easily affected by various effects such as formation water dilution and chromatographic separation.

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