Pressurization Characteristics and Proppants Transport of Pulse Jet Fracturing with CFD-DEM Coupling Method

Hydraulic jet fracturing, which integrates hydraulic sand jet perforation and hydraulic fracturing, is widely used in the stimulation of low permeability reservoir. However, due to the complexity of the fluid-solid interaction, the effect of pressurization characteristics and proppants transport in the perforation hole are still unclear. Therefore, in this paper, the pressurization characteristics and proppants transport of pulse jet fracturing are investigated under different pressure amplitude, angular velocity, average pressure, nozzle diameter and perforation diameter with the CFD-DEM (Computational Fluid Dynamics and Discrete Element Method) coupled method. Results indicates that the effect of pressure amplitude, average pressure are positively related to the maximum velocity and maximum total pressure, while the effect of nozzle diameter is positively correlated with the maximum velocity, and the maximum total pressure has a relatively small effect. The effect of perforation diameter is negatively related to maximum velocity. It can be seen that pulsed jet fracturing can effectively relieve the large number of proppants blocking present around the perforated inlet of a single section of the pulse jet fracturing model (SPJFM). But when the proppants are of a certain size and the nozzle diameter is very small, it is difficult for the proppants to enter the perforation. And the smaller the diameter of the perforation, the less proppant enters the perforation, and some of the proppant appears in the annular section. By reasonably designing the optimal parameters, the pulsed jet can maximize the pressurization, helping optimize jet fracturing application parameters.