Carboxylized graphene oxide nanosheet for shale plugging at high temperature

Graphene oxide nanosheet was carboxylated and the relative percentage of carboxyl groups was 24.3% in carboxylated graphene oxide (GO-COOH), which is pretty higher than previous reports. After hydrothermal at 180 degrees C, GO-COOH kept the particle size distribution at 600 nm and the retaining carboxyl groups made GOCOOH still have pretty good dispersibility, thus increasing the high-temperature resistance. Moreover, the time of core pressure transmission of 0.1 wt% GO-COOH was 12 times that of 1 wt% silica and 4 times that of 4 wt% polypropylene glycol and polyether alcohol, indicating GO-COOH can be a novel and efficient hightemperature resistant plugging agent used in water-based muds.