Abstract Because of the every time higher complexity of the petroleum and gas reservoirs, their analysis have become into an intensive job that, to get a real behavior, most of then consider numerical modeling of the different phenomena inside the reservoir.Two aspects that have shown transcendental importance in reservoir fluid flow are the compositional characteristic of the fluid and the rock stress sensitive.Several authors have analyzed independently every characteristic, remarking every time more their importance. A fully implicit model to study this problem is developed on a cylindrical finite difference, point distributed grid. Compositional modeling is performed by means of a 12- pseudocomponent Peng-Robinson equation of state with volume translation, tuned to actual PVT and field data of a gas condensate fluid.Michelsen's phase stability test is also considered in the VLE calculation procedure.Because of the proper multiphase flow-effective stress law is unknown, and the capillary pressure for the fluid-rock system under consideration is negligible, it is approached to zero in this research.The geomechanical rock deformation calculation is based on the non-linear elastic model. To comprehend the involved phenomena, this model must guarantee numerical stability.It has to be taken into account that in order to obtain numerical stability the time step (?t) used in the models should be long (opposite to the requirements of non coupled models).It was realized that the influence of geomechanical properties at the bottom hole pressure is evidenced by long production time simulations.The major contribution of this research is that it helps to determine the pressure sensitivity to important factors such as boundary and initial conditions, and compositional fluid presence in the reservoir. This study identifies the necessary ?t values to ensure numerical stability.The model shows that when c[bc] get values closed to the rock compressibility, c[r], the pore pressure fall is every time higher.Some other studied parameters emphasize both, the complexity of the phenomenon and the strong influence of some variables on it.