Development of stress sensitive reservoirs, especially in challenging environment, is raising awareness that geomechanics is a vital aspect of reservoir management. Understanding reservoir geomechanical behavior becomes more and more important for petroleum industry. A significant changes in formation pressure caused by depletion will induce deformation and stress/strain changes in the reservoir and the surrounding formation, understanding in-situ stresses and how stress changes in and around the reservoir due to depletion is important in a multidisciplinary approach to reservoir characterization and management. These changes in stresses/strain affect the reservoir as well as the overburden and underburden formation, which directly affect drilling and stimulation operations strategies. Reservoir compaction, shear casing and well damage, cap-rock integrity, fault reactivation and sand production can occur during reservoir depletion. To address these issues, 3D geomechanical models have been developed (which describe the state of stresses in the reservoir and overburden).