Effect of the Elastic Constants on the Pressure Behavior of Vertical Wells

Abstract

fax 01-972-952-9435. AbstractEveryday, it is more frequent and common to adequately know the dynamical behavior of stress and strain sensitive formations and to improve their geomechanical characterization, as well. For this purpose, a coupled simulator of fluid flow and rock deformation was used in this study to investigate the impact of the elastic constants of the rocks during a well pressure test. The results were compared with those obtained for a reservoir with average properties in which the geomechanical effects were neglected.The numerical experiments were focused on simulating drawdown tests for four different scenarios as follows: a standard case without geomechanical effects, two cases with isotropic initial state of stress and two cases with anisotropic stress. For interpretation and comparison purposes, we utilized the TDS technique to determine the reservoir parameters of the simulated pressure data. The results allow us to visualize that Young's modulus causes a pronounced effect on the pressure test during pseudosteady-state flow which leads to a wrong estimation of reservoir drainage area; a range of values were established above which its variation does not cause important effects. On the other hand, it was found that variations of Poisson's ratio are not significant since they fit in a small range of the values customary reported in the literature.