A kind of preparation method of post-hydrolyzed ultrahigh molecular weight comb polyacrylamide

Abstract

The invention discloses a method for preparing post-hydrolyzed ultra-high molecular weight comb-shaped polyacrylamide, which comprises the following steps: S1: dissolving 20% ​​to 25% of acrylamide in 70 to 77.5% of distilled water according to mass percentage, and then adding 2.5 to 77.5% of acrylamide 5% of N-triethyl-(4-vinylbenzyl) ammonium chloride, sodium styrene sulfonate, N-methylmaleimide, 4-hydroxybutyl vinyl polyoxyethylene ether After ultrasonic dispersion of the functional side group mixed monomer, a mixed solution is obtained; S2: Cool the mixed solution to 0-5°C, add a complexing agent, stir for 0.5-1 hour, and add a chain transfer agent after passing nitrogen to drive oxygen. In the case of continuous nitrogen flow, add an initiator to initiate the polymerization reaction, and seal the reaction for 3-8 hours; S3: post-hydrolysis; S4: drying, crushing, and sieving. The polyacrylamide prepared by the present invention has a rigid comb-shaped structure. Because the molecular side chains repel each other, the high temperature resistance, salt resistance and shear resistance of polyacrylamide are effectively improved, so that it can be used as a kind of high-salt high-temperature formation in oil fields. Ideal oil repellant.

Description

technical field [0001] The invention belongs to the field of functional polymers, and in particular relates to a method for preparing a post-hydrolyzed ultra-high molecular weight high-temperature-resistant comb-shaped polyacrylamide. The introduction of hydrophilic and lipophilic rigid side groups can effectively improve the polyacrylamide in high salinity. and viscosity-increasing properties at elevated temperatures. Background technique [0002] At present, ultra-high molecular weight partially hydrolyzed polyacrylamide is the most widely used polymer in enhanced oil recovery. It is mainly prepared by the hydrolysis of polyacrylamide in an alkaline environment or the copolymerization of acrylamide and sodium acrylate. Ultra-high molecular weight polyacrylamide has a molecular weight of more than 25 million, and has a large molecular hydrodynamic volume, so its solution has high initial viscosity and residual viscosity, but because ultra-high molecular weight polyacrylamid...

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Problems solved by technology

Ultra-high molecular weight polyacrylamide has a molecular weight of more than 25 million and has a large molecular hydrodynamic volume, so its solution has high initial viscosity and residual viscosity. However, because ultra-high molecular weight polyacrylamide is generally a straight chain structure, Under high-shear conditions, its molecular chain structure is unstable, easily broken or entangled, resulting in a sharp drop in viscosity and viscoelasticity, and a decrease in water-oil flow rate ratio, which ultimately affects the effect of polymer flooding. In addition, with the increase of molecular weight, It will cause the problem of difficult dissolution, and the performance of ultra-high molecular weight polyacrylamide against high temperature and high salt still needs to be further improved

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