A core-shell polymer microsphere and its preparation and application

Abstract

The invention relates to a core-shell type polymer microsphere and its preparation and application. After adding deionized water, an emulsifier and a dispersing agent into a reaction kettle, slowly stirring and dissolving, adding styrene-based monomer and vinyl polymerization crosslinking agent and initiator, then pass nitrogen to replace the air in the reaction kettle, heat up to 70-85 °C, and form a core structure after the reaction; dropwise add a crosslinking agent containing acrylate, styrene-based monomer, vinyl polymer and The reaction solution of the initiator reacts on the surface of the core structure to form a shell structure, cools down to room temperature, discharges the material, and filters to obtain the product; the inner core structure of the core-shell polymer microsphere is composed of styrene-based monomer and vinyl polymer. It is formed by the reaction of cross-linking agent; the microsphere shell layer is copolymerized by acrylate, styrene-based monomer and vinyl polymer cross-linking agent, and the microsphere shell layer undergoes volume expansion under the action of downhole oil and gas, bonding and sealing The micro-cracks in the cement sheath or the micro-gap at the interface are blocked, and the core part of the microspheres ensures that the microspheres have sufficient strength after expansion.

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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