The technique for stimulating an oil field through hydraulic fracturing consists of pumping into the oil bore the fracturing fluid mixed with a material to hold the fracture open, called proppant. One of the difficulties in this process is the occurrence of proppant flowback into the well bore during oil production, causing several problems that can result, in critical situations, in a definitive interruption of the oil production. Control of proppant flowback represents a great challenge for the petroleum industry. Some empirical models - Stimlab correlation, propped- free wedge model, minimum fluidization velocity, semi-mechanistic model - were developed for prediction of proppant flowback, yet they do not encompass all variable that play a role in this complex phenomenon. An alternative is to employ the discrete element method in order to computationally simulate the instability of the granular package. The main goal of this thesis is to investigate the proppant flowback phenomenon, through a 3D model of the fracture, particles and flow conditions using the computational program PFC3D, a code based on the discrete element method. The input data (type of proppant, temperature, characteristics of the fluid and proppant, etc.) relate to 4 main scenarios that consider fractures under several levels of stress closure and drag forces. The numerical results computed from 2D and 3D analyses were discussed, as well as comparisons were done with the predictions obtained with empirical methods.