Geomechanical model as the basis of a solid can be foundation for the majority of upstream petroleum studies and new approach to low-risk drilling with high efficiency ratio and to reduce the damage to the reservoir. Use stress directions in the oil fields is critical to solving engineering and geological problems. Direction and magnitude larger horizontal stress is effective to the creation and direction of the induced tensile fractures in the wellbore. Nowadays, in the oil industry when predictions for drilling operations planed, should be attention to rock mechanics issues in well Stability and choosing suitable drilling mud weight because the lack of attention could be spending a lot of time and cost, to prevent these problems should also be considered rock mechanics predictions. In this research, at first tried to construct 1-D and 3-D geomechanical model, Then the stability of the well wall is discussed. Geolag software has been used to interpret the drilling logs and the extraction of modules as well as the construction of a geomechanical 1-D model, With the interpretation of the Caliper, Sonic, Density, Gamma Ray and Dsi logs for four wells located in the Maron filed, petro-physical values, dynamic modulus and pore-pressure are obtained. Using experimental relationships, the values of petro-physical parameters and rock mechanics such as porosity, vertical stress, horizontal stresses, pressure stress, static elasticity modulus, Poisson ratio, cohesion, and internal friction angle are calculated. The output of the 1-D models of Geolag software is the input data of Ptrel software for constructing a 3-D static model. In this software to build a 3-D model Geostatistical methods of Gaussian sequencing simulation and Gaussian random function simulation was used. Finally, oftware and Mohr-Columb's failure criterion were used to Analysis the well stability With the runing model that made, relatively deep break-out in the upper parts of the well And discontinuous break-out in the middle of the well, due to the low drilling mud pressure and the presence of a weak shale layer and Chilean sand in this depth. After the support system is applied, the displacement rate decreases and the wall becomes stable. By investigating the effect of pore-pressure, it was determined that with increasing pore-pressure, the instability of the well and the amount of displacement increased. If drilling mud pressure be less than actual observed a similar situation to the increase in pore pressure and by increasing the drilling mud pressure of 10 MPa, the well will be stable and displacements will be reduced. For calibration of the results of stability analysis and break-out of 3-D used caliper log that Which has a good conformating with the 3D model. in this research, the 3-D static model was constructed using the top points and used Sakurai experimental relationships to check the allow displacement.