Objective A new hydrophilic epoxy resin-based elastic particle is prepared to solve the problem of the strength decline of cement stone caused by the incorporation of existing elastic fillers.

Method A new type of elastic resin particle (E-RP) was prepared by modifying epoxy resin with liquid nitrile butadiene rubber (CTBN) and nano-SiO₂, and the chemical composition, hydrophilicity, dispersibility, microstructure and mechanical properties of E-RP were studied through Fourier transform infrared spectroscopy, contact angle, ultraviolet spectroscopy, XPS, scanning electron microscopy and uniaxial compression.

Result The contact angle between E-RP and water was 54.5°, which had good compatibility with cement slurry, and the successful reaction of CTBN with some epoxy groups and the introduction of flexible segments made E-RP have higher elastic deformation ability, and the compressive elastic modulus of E-RP was reduced by 47.9% compared with pure resin. The addition of E-RP would slightly reduce the fluidity of cement slurry, and improve the compressive strength of cement stone and the deformation ability under load. Compared with the blank cement stone, the elastic modulus of the cement sample containing 4 wt% E-RP particles was reduced by 37.5%.

Conclusion E-RP can maintain good dispersibility and interfacial bonding in the cement matrix, thereby alleviating the strength decline of cement stone, and E-RP can consume load energy through its elastic deformation and debonding with the cement matrix, effectively reducing the brittleness of cement stone and ultimately improving the quality of well cementing.