A kind of dynamic covalent bond cross-linked oil displacement polymer and preparation method thereof

Abstract

The invention relates to a dynamic covalent bond cross-linked oil-displacing polymer and a preparation method thereof. In the present invention, acrylamide is used as the main monomer to increase the length of the molecular chain, thereby increasing the frictional resistance between the molecular chains to improve the viscosity of the solution, and diacetone acrylamide is used as the functional monomer to copolymerize with acrylamide to introduce the ketone carbonyl group into the polymer chain Cross-linking with adipic hydrazide is achieved, resulting in nonionic polymers cross-linked with dynamic hydrazone bonds. The absence of ions in the polymer chain avoids charge shielding and flocculation of various salt ions, and can maintain high viscosity in high salinity water. And the polymer uses the acylhydrazone bond that can be dynamically formed and dissociated as the chemical cross-linking point. As a stimulus-responsive dynamic chemical bond, it not only maintains the reversibility of physical cross-linking, but also has the strength of chemical cross-linking. Reversible formation and breakage can be achieved under external environmental stimuli to overcome the disadvantages of poor shear resistance of traditional polymers.

Description

technical field [0001] The invention relates to a dynamic covalent bond cross-linked oil-displacing polymer and a preparation method thereof, belonging to the technical fields of petroleum exploitation, transportation and chemical industry. Background technique [0002] Oil is the lifeblood of economic development, and my country's foreign dependence on oil is as high as 72%. At present, many water-flooding oilfields in China have entered the middle and late stage. During this period, due to the heterogeneity of the reservoir and the unfavorable mobility ratio, there is still a large amount of remaining oil in the formation after water-flooding, and the water injection recovery factor is less than 40%. %, the water content of the reservoir is generally above 95%, and the problems of viscous fingering and tongue feeding are serious, generally manifested as high water cut in oil wells, low production, and poor economic benefits of mining. In order to ensure stable oil producti...

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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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