Simply, in oil engineering, rock mechanics or geomechanics deals with the impact of stress and resistance of rock on the behavior of formations as a result of oil activities. In all periods of hydrocarbon fields’ development, i.e. from the primary stages of exploration when basic questions such as predicting pore pressure before drilling are propounded to the stages of evaluation, development and extraction of fieldwhere operator faces some problems such as optimizing well stability for drilling and predicting the closure of faults and crack permeability, geomechanics-related issues are appeared. In addition to the high importance of geomechanics in reservoir management and some issues such as well stability, sand production, hydraulic fracture, and land subsidence, recently, an increasing interest in developing the relation between fluid flow simulators and geo-mechanical models has been also observed . Oil and gas reservoirs production is accompanied with some change in geo-mechanical properties. These changes influence the status and amount of stress under the surface. As reported by previous studies, this phenomenon involves many problems and challenges in developing and producing non-rigid, chalk, fractured, and highly compact reservoirs of the world. Geo-mechanical changes can strongly influence formation compaction, land subsidence, reservoir permeability, and sweep efficiency in flooding, water breakthrough, and faults reactivation