Abstract: In order to improve the proppant displacement in the fracture and enhance the fracturing stimulation effect, the experiment on proppant carrying capacity of fracturing fluid was conducted with experimental simulation method and visual-panel fracture device, the formation of in-fracture sand bank was characterized in combination with the microscopic movement trajectory of the proppant particles and the macroscopic shape of sand bank, the difference in sand carrying modes was analyzed between of viscous and non-viscous fracturing fluids, and the effects on the displacement pattern of sand dike was studies in terms of fracture inter-perforation disturbance, fracturing fluid displacement, fracturing fluid viscosity and construction sand ratio. The results indicated that the proppant in fractures migrated under the joint action of fluidization and sedimentation, mainly dragged and transported under the action of fluidization; an immobile thin layer of fluid was formed between the fluidized layer and sand bank in viscous fracturing fluid to support the particles, reducing the friction and collision between the fluid and the particles; the formation of the sand bank includes four stages, that is, sand bank formation, development, balancing and piston-like forwarding, the formed sand bank could be characterized by accumulating angle, balancing height and advancing angle under the joint effect of perforation disturbance and fluid erosion, and there were no sand zones in the fractures near the wellbore and in the direction of fracture height; the balancing height of the sand bank mainly depended on the movement speed of proppant particles, inversely proportional to the construction displacement and the fracturing fluid viscosity and directly proportional to the sand ratio. This study provides a reference for the optimization of fracturing operation parameters.

Key words: fracturing, proppant, fracturing fluid, sand bank displacement pattern, perforation disturbance