Preparation and properties of resin coated ceramic proppants with ultra light weight and high strength from coal-series kaolin

In this study, low-cost coal-series kaolin and ZnO powders were employed to prepare petroleum fracturing proppants with low density and high strength. Furthermore, the method of resin coating was used to optimize the performance of ceramic proppants. The bulk density, apparent density and breakage ratio of specimens were systematically investigated as the function of sintering temperature and the content of ZnO. Moreover, the reason that epoxy resin coating could increase the strength and reduce the density has been discussed by means of 3D modeling. The morphology structure and phase composition of specimens were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The phase transition of kaolin was studied using thermal techniques (TG/DSC). The experimental results revealed that the proppants sintered at 1350 °C with the addition of 2 wt% ZnO had the best performance. The apparent density and breakage ratio under 35 MPa was 2.662 g/cm3 and 2.44%. The addition of ZnO could promote the densification behavior of the sample. The coated proppants with 12 wt% epoxy resin displayed excellent performance with 2.270 g/cm3 of apparent density and only 1.16% of breakage ratio under 69 MPa, which had great advantages in the application of deep well oil and gas development.