Hydraulic fracturing is a well-stimulation technique that is most suitable to wells in low to moderate permeable reservoirs that do not provide commercial production rates even though formation damages are removed by acidizing treatments. In fact this technique was provided to increase the flow rate from rocks and discontinuity features into the well. Initiation and propagation of the tensile fractures in the rock vicinity to a well or on the tip of pre-existing fractures causes by injected fluid pressure in a packed section of a well called hydraulic fracturing process. Efforts have been made to study the aforementioned phenomenon using different analytical, experimental and numerical techniques. However they did not consider closely conceptual geometrical models with reality for modeling the hydraulic fracturing test numerically in different laboratory and blocky scales which is the main objective of this research work. In this study, a systematic numerical laboratory experiments has been carried out using a three dimensional Particle Flow Code (PFC 3D ) based on Ahvaz – Bangestan petroleum reservoir data. At blocky scale also, a three dimensional Discrete Element Code (3DEC) with concept of fictional joint technique has been facilitated and the effects of operating parameters of injected flow such as flow rate and viscosity and also in-situ stress rate on the performance of the hydraulic fracturing process were studied. The simulation results by PFC 3D show that the fracture is formed along the maximum horizontal in-situ stress direction. Furthermore, the results of sensitivity analysis about the effects of operational parameters of fluid and also far field stress ratio on the created and propagated fractured by 3DEC represent that when fluid viscosity is increased, the rate of fracture propagation is decreased, while joint opening and wellbore pressure concentration is increased. In the other hand, with increasing fluid flow rate, fracture propagation rate, concentration of pore pressure is increased. Also with increasing in-situ stress rate the pore pressure in the direction parallel to the maximum horizontal stress is increased. When far field horizontal stresses are equal, pore pressure and displacement values is greater than the other cases while the fractures are less scattered.
