Characterization of Proppant Flowback in Hydraulic Fracturing Rough Fractures

In the process of fracturing, proppant flowback is unavoidable, and excessive proppant flowback will cause sand plugging in the wellbore, change the morphology of proppant fractures, reduce the effective flow‐conducting capacity of fractures, weaken the effect of fracturing to increase production, and affect the extraction of hydrocarbons in the later stage of the fracturing process. At present, the research on proppant flowback during fracturing and re‐discharge process mainly focuses on the force of proppant and its critical flowback rate at the time of startup, and there are fewer studies on the factors affecting proppant flowback, and there is not yet a theoretical model to specifically analyze the flowback characteristics of proppant in a rough fracture. Combining the above reasons, this paper constructs a three‐dimensional numerical simulation model of proppant flowback in rough fracture by using the coupled computational fluid dynamics‐discrete element method to study the factors affecting proppant flowback in rough fracture, and it is found that the rough fracture can reduce the flowback of proppant by comparing the flowback of proppant in the smooth fracture and the rough fracture. Meanwhile, it is clearly understood that the flow rate of return fluid and proppant particle size are the main influencing factors affecting proppant flowback. This study can provide theoretical references for the program design and field construction of the actual fracturing return phase.