Core-shell type polymer microspheres, preparation and applications thereof

Abstract

The present invention relates to core-shell type polymer microspheres, preparation and applications thereof. The preparation comprises: adding deionized water, an emulsifier and a dispersing agent to a reaction kettle, slowly stirring and dissolving, adding a styrene base monomer, a vinyl polymer cross-linking agent and an initiator, introducing nitrogen to replace air of the reaction kettle, heating to a temperature of 70-85 DEG C, reacting to form a core structure, adding a reaction solution containing acrylate, a styrene base monomer, a vinyl polymer cross-linking agent and an initiator in a dropwise manner, forming a shell structure on the core structure surface, cooling to a room temperature, discharging the material, and filtering to obtain the product. According to the core-shell type polymer microspheres of the present invention, the internal core structure is formed by the reaction of the styryl monomer and the vinyl polymer cross-linking agent, the shell layer of the microspheres is formed through the copolymerization of the acrylate, the styrene base monomer and the vinyl polymer cross-linking agent, and produces volume expansion under the downhole oil-gas effect so as to bond and seal the micro-crack in the cement sheath or the interface micro-gap, and the sufficient strength of the microspheres after expanding is ensured through the core portion of the microspheres.

Description

technical field [0001] The invention relates to a core-shell polymer microsphere and its preparation and application, in particular to a self-healing polymer microsphere for improving the sealing performance of an oil and gas well cementing cement sheath and a preparation method thereof. Background technique [0002] Cement-based materials are inherently brittle materials with microscopic defects. Under the action of force or other factors, damage will occur, resulting in micro-cracks. If the micro-cracks continue to expand to the entire matrix, it will lead to the reduction of the physical properties of the cement matrix and the final destruction. , so it is extremely important to be able to detect and repair such cracks in time. The cement sheath of oil and gas well cementing is a cement-based material, which also has congenital brittleness and internal defects. The purpose of oil and gas well cementing is to use Portland cement to seal the annular space between the casin...

AI Technical Summary

Problems solved by technology

Due to the long-term high temperature and high pressure underground and high shear during cementing construction, the environment is very different from conventional materials, and it is difficult to treat it through external photothermoelectric intervention at a depth of several thousand meters underground. At present, the existing self-healing technology has relatively high Large limitations, still can not solve the oil and gas well cement sheath micro-crack damage to improve the sealing performance of cement sheath

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