Preparation and properties of epoxy semi-coated quartz sand proppant decorated with stearic acid functionalized TiO2 nanoparticles

In this work, the hydrophobic and oleophilic epoxy semi-coated quartz sand proppant decorated with stearic acid functionalized TiO2 nanoparticles is successfully prepared. The unique semi-coated structure is characterized by SEM, SDF, and TEM. Compared with raw quartz sand proppant, the water contact angle of the epoxy semi-coated quartz sand proppant can even reach 141.6°, which is due to the rough surface and hydrophobic coating induced by semi-coated epoxy and hydrophobic stearic acid-modified TiO2. Meanwhile, the water contact angle could be adjusted by controlling the weight content of quartz sand. Moreover, the semi-coated proppant can maintain its hydrophobicity after treated by boiling water for 4 h, indicating improved thermal stability. The physical properties including bulk density (1.44 g/cm3), apparent density (1.40 g/cm3), acid solubility (3.43%), and breakage rate (1.26%) of the semi-coated proppant decorated with stearic acid functionalized TiO2 nanoparticles are improved. The thermal stability, acid solubility, and flow conductivity are analyzed as well. This work could provide a new idea for the preparation of quartz sand proppant to enhance the petroleum and gas production through hydraulic fracturing technology.