Experimental study of rheology and filter loss performance of nano-ZnO-modified VES fracturing fluid.

AbstractViscoelastic surfactant (VES) fracturing fluid is characterized by low filtration loss, high sand carrying and environmental friendliness for applications in low permeability reservoirs and unconventional oil and gas extraction. In this work, the VES fluid was prepared with 0.7 wt% trimethylstearylammonium chloride (OTAC), 0.14 wt% sodium salicylate (NaSal), and 0.1 wt% nano-ZnO particles to form a nanomodified VES fluid. The rheology and dynamic filtration were conducted. The results showed that the fluid filtration loss of the VES system was significantly reduced compared to that of the conventional polymer disperse system. The stabilization of the VES fluid is enhanced by the incorporation of ZnO nanoparticles. It effectively increases the viscosity of the fracturing fluid at high temperatures. It makes it easier to form filter cake, which significantly reduces the amount of filtration loss. With the increase in core permeability and displacement pressure difference, both the filter loss and the loss coefficient increase. In addition, the formation damage rate of nanomodified VES fluid is only 34%, which is less than the traditional Guanidine Fracturing Fluid. [ABSTRACT FROM AUTHOR]