This dissertation aimed to present the main differences between commercial software for hydraulic fracturing with the development of a three - dimensional discrete fracture network and conventional fracture design software, presenting an analysis of the effects of the variation of the main parameters that influence the simulation results on a real case (Total Leakoff Coefficient and Spacing between Fracture Plans). As a clarification of the main unconventional fracturing scenario, the description and main properties of shale gas/oil were presented. Following the theories of the orthogonal geometries and the importance of the natural fractures that support the doctrines of the DFN. While in the conventional fracture, a planar fracture model with two symmetrical wings is used in relation to the well, in the shale gas/oil fracturing, the currently accepted model is the creation/activation of a dominant fracture and a network of parallel fractures and fractures orthogonal to the dominant. The modeling assumptions, the additional equations in relation to the conventional hydraulic fracture, the criteria adopted for the solution of these equations and the additional input data related to the fracture network were presented. To illustrate the conventional modeling differences and discrete fracture network, we have presented the governing equations of a conventional pseudo-three-dimensional simulator (P3D) and the governing equations of the simulator with the creation of a fracture network studied (MShale). Since additional input data is the biggest challenge for hydraulic fracturing designers, a chapter on them has been presented, with an example of actual commented data input and a chapter describing the simulator data output. It was concluded that the total filtration coefficient has a great impact on the geometry and conductivity of the dominant fracture and the network of secondary fractures, also influencing the concentrations of proppant, as it was also proved that the interaction between fractures corresponds to the variation of the assumed spacing between the fracture planes. It was verified that conventional fracture design software should not be used in scenarios of non-conventional reservoirs, because the results are unrealistic. It was pointed out deficiencies of the software of hydraulic fracturing with analyzed network of fractures, as the consideration of constant coefficient of filtration throughout the operation. It is hoped that this dissertation will be useful to hydraulic fracturing designers when dealing with unconventional reservoirs such as shale gas / oil and to stimulate the interest of the academy on this subject.