Study on proppant reflux law based on finite element simulation

In this paper, Fluent software was used to simulate the proppant reflux law, and finite element method was used to study the stress of proppant particles at each part of a single fracture and the flow law of proppant particles in a single fracture when reflux occurred. The simulation results showed that: flowback fluid viscosity and flowback flow rate have great influence on proppant reflux law, so it is required that the fracturing fluid system has a small viscosity to ensure that the proppant system stays deep in the fracture. On the other hand, it is necessary to control the flowback flow rate to prevent the proppant from being carried by the fracturing fluid into the bottom hole. Proppant size has little influence on proppant flow back, and proppant flow escape is unavoidable during flowback. For proppant flow control, it is necessary not only to control the viscosity and flowback speed of fracturing fluid after breaking rubber, but also to take corresponding flowback process measures and special proppant system to ensure that proppant stays in the deep fracture.