Pore Pressure Stress Coupling in 3D - impact on

Abstract

Knowledge of the complete stress tensor in 3D and is tempo-spatial evolution is crucial for reservoir stability aspects and depletion plannings in general. We investigate the poro-elastic effect of production/injection induced pore pressure variations on the components of the complete total stress tensor in 3D for a point source in a homogenous, fully saturated isotropic medium. Furthermore, we provide a simple analytical base for the long-term changes of stress components the results of our analysis show that the coupling effects between pore pressure and stress tensor components depend on the locality in the reservoir with respect to the producation/injection point. We investigate systematically the the dependence of our findings for different tectonic regimes and reservoir depths. The results show how localized changes of shear stresses can lead to unexpected results such as different fracture orientations or modifications of the drilling window. For complex production scenarios with numerous injection and depletion wells within a reservoir numerical modelling is a means to investigate the spation-temporal evolution state of stress during the lifetime of a reservoir. Our theoretical approach helps to understand the results of numerical modeling.