Fabrication of a Dual-Effect Repair Agent for the Self-Repair of Cement Cracks and Antichanneling

Under suitable humidity and pressure conditions, the severe corrosion of cement caused by CO 2 can seriously damage the integrity of wellbores and shorten the life of oil and gas wells. Smart self-repairing materials that can plug microcracks play a vital role in cementing. In this study, we designed a dual-effect repair agent that combined a smart hydrogel with modified styrene–butadiene latex (SBL). The hydrogel showed an excellent CO 2 response, swelling with a swelling ratio of 12.4 g/g under a CO 2 atmosphere and plugging the microcracks of cement with a repair efficiency of 80%. In addition, the modified SBL exhibited excellent flexibility and a small particle size (approximately 200 nm), enabling it to enter nanometer-scale cracks in cement and aggregate to form a nonpermeable film, further increasing the repair efficiency to 92%. In addition, cement slurries containing the prepared hydrogel and SBL exhibited antichanneling ability with the rapid development of early-stage strength and a short gel transition time. We believe that the prepared dual-effect repair agent has significant potential for oil-well cementing.