Effects of pyroelectric nanoparticles on the temperature resistance of VES fracturing fluids

Abstract The production of oil and gas in China predominantly relies on low-permeability reservoirs and unconventional resources. Enhancing the temperature stability of fracturing fluids is a critical strategy to boost recovery from unconventional oil and gas reservoirs. This study investigates the thermal stability of VES fracturing fluids through rheological testing, aiming to identify the optimal system and dosage based on their thermal resistance. The findings indicate that at 60°C, the zero-shear viscosity of the base fluid was 9.9 Pa·s, with a relaxation time of 0.079 s. Upon addition of Pyroelectric nanoparticles, the zero-shear viscosity was maintained at 14.6 Pa·s, with a relaxation time of 0.161 s. At 90°C, the viscosity of the VES fracturing fluid containing Barium titanate nanoparticles remained at 66.7 mPa·s, which is 3.03 times that of the base fluid. Similarly, at 100°C, the viscosity was 29.26 mPa·s, 4.12 times that of the base fluid. However, Aluminium oxide and Silicon dioxide nanoparticles did not exhibit significant improvements. The apparent viscosity of the VES fracturing fluid decreased to 50 mPa·s at a shear rate of 170 s −1 , and the thermal stability was enhanced by 12°C with the inclusion of Pyroelectric nanoparticles. The synergistic effect of Pyroelectric nanoparticles and surfactants offers a novel approach for optimizing the temperature resistance of fracturing fluids suitable for high-temperature applications.