Abstarct: The well integrity is an objective and a solution in order to protect human life, the environment and, eventually, the amount of oil produced during the life of the well. The necessity to maintain and repair the wells with long life and, on the one hand, high costs for the construction of new wells cause that studying the integrity of the well to be a vital element in managing the longevity of a well. Therefore, the better understanding of cement behavior plays an important role in ensuring the integrity of the well and can effectively be considered in preventing or controlling the failure of cavity tubes. This matter, while improving the level of security of the production process from the well, causes to control the unexpected and unconventional costs of oil and gas production (maintenance and repairing costs for wells, secondary cementing, etc.), which in some fields, such as Maroon and Kupal is very serious. In this research, first, a one-dimensional geomechanical model is constructed of a well-covering formation using the petrophysical data of the considered well. At this stage, geomechanical features of the formation are estimated. The mechanical data related to the cement is determined using laboratory tests. The mechanical parameters of the cement sheath are determined using single-axis, three-axis and Brazilian tests on cement samples. Also, a direct cutting test on the artificial gap between the cement and the formation is also done, which the friction parameters of the contact surface between the cement and the formation are determined. Then, a reference numerical model is formed in two sections of the well with ABAQUS software using input data and according to the environmental conditions of the well. The critical model is chosen by comparing the constructed models and in the following, sensitivity analysis and parametric studies are conducted in order to examine the effect of situations of in situ stresses, friction parameters of contact surfaces and mechanical parameters of cement, and their effects are examined on the integrity of the well. The results show that the strain of plastic in the cement is increased and the casing safety factor is decreased by increasing the ratio of horizontal to vertical stresses and the difference in horizontal stresses. The cement sheath with high Young’s modulus, Poisson coefficient, adhesion and low friction angle, have the highest concentration of plastic strain. Also, the strain of plastic in the cement is decreased by increasing friction of contact surfaces of formation - cement and cement - casing.