Urchin-like SiO₂ Nanospheres for Enhancing the Performance of Clean Fracturing Fluids

In this study, nanofiber-surrounded urchin-like SiO 2 nanospheres (SiO 2 –NUs) were synthesized using the template method and effectively reinforced clean fracturing fluids comprising cetyltrimethylammonium bromide and sodium salicylate. The SiO 2 –NUs particle size and morphology were measured using transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. The composition of SiO 2 –NUs was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. After the introduction of SiO 2 –NUs to the clean fracturing fluids, the rheological properties, salinity resistance, and dynamic filtration loss were all substantially improved. The viscosity increased from 10,781 to 22,991 mPa·s, which was more than 2 times higher. This enhancement was due to the ultrahigh specific surface area of SiO 2 –NUs and the formation of micelle–nanoparticle junctions. Finally, the interaction between SiO 2 –NUs and wormlike micelles was elucidated, and a mechanism was proposed for SiO 2 –NUs enhancing wormlike micelles. The results of this study should broaden the application scope of nanomaterials in the fracturing fluids.