Proppant is the key material of hydraulic fracturing, which directly determines the fracturing effect of hydraulic fracturing. With the gradual development of unconventional oil and gas, conventional proppants cannot meet the performance requirements. Conventional proppant has problems such as proppant crushing, backflow, and inability to achieve long fracture filling. Nanocomposites have excellent physical, mechanical, chemical, and thermal stability properties and have broad application prospects in proppant coating materials. Coating nanocomposites on the surface of conventional proppants can greatly improve their properties, including sphericity, compressive strength, density, acid and alkali resistance, hydrophobicity, and suspension capacity. Before preparing the coated proppant, it is very important to understand the properties of the coating material and the proppant substrate. Hence, this paper reviews the excellent properties of nanocomposites and coated proppants. Firstly, the performance requirements of hydraulic fracturing technology for unconventional oil and gas reservoirs on proppant are introduced. Second, the properties of nanocomposites used in proppant coatings are reviewed. Third, the application of nanocomposites in proppant coating and the procedure of proppant coating are introduced. The latest coating proppants are summarized. Finally, the existing research gaps and challenges are presented, and the possible future development directions of coated proppants are given. Ceramic coated proppant has a good application prospect because of its excellent performance.
