A kind of low expansion speed nanoscale water-absorbing microsphere and preparation method thereof

Abstract

The invention relates to a nanoscale water-absorbing microsphere with low expansion speed and a preparation method thereof. The preparation method includes: preparing a water-phase mixed liquid: uniformly mixing acrylamide, acrylic acid, cationic monomers, a cross-linking agent and water, and then adding alkaline substances to obtain a water-phase mixed liquid; preparing an oil-phase mixed liquid: mixing an oily solvent, The hydrophobic monomer and emulsifier are mixed evenly to obtain the oil phase mixed liquid; polymerization: the oil phase mixed liquid is homogenized, then nitrogen and oxygen are removed, and then an initiator is added to initiate polymerization, and the temperature of the system is controlled by refrigeration equipment Not exceeding 70°C; Post-treatment: After the polymerization reaction is completed, nonylphenol polyoxyethylene ether is added to the mixed solution after the reaction to obtain nano-scale water-absorbing microspheres with low expansion speed. The particle size distribution range of the microspheres prepared by this method is small, ranging from 30 to 100 nm, and the expansion speed is slow, and the initial expansion time is between 1 and 2 hours, which is especially suitable for plugging special dense bottom blocks.

Description

technical field [0001] The invention relates to the technical field of profile control and water shutoff for increasing production in oilfields, in particular to nanoscale water-absorbing microspheres with low expansion speed and a preparation method thereof. Background technique [0002] The loss of the oil displacement agent system has become a widely faced problem in the exploitation of crude oil, and these problems will greatly affect the production and benefits of the oil field. In the later development process of polymer flooding, due to the existence of many tiny pores in the formation, under the high pressure conditions during the oil displacement process, the oil displacement agent permeated and lost from the pores, resulting in a lot of waste. Therefore, the problem of water plugging and profile control in oilfields is becoming more and more severe. At present, polyacrylamide aqueous solution and cross-linking agent are used most in oilfields for selective water pl...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problem that existing preparation methods cannot produce polymer microspheres with particle diameters within 100nm, the present invention provides a method for preparing nanoscale water-absorbing microspheres with low expansion speed

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