Production versus injection induced poroelasticity surrounding wells

This article presents a novel assessment of flow-induced geomechanics in a poroelastic layer, incorporating confining effects of sealing rocks. For the first time, production-induced temporal principal plane variations, and potential failure mechanism/s are analytically evaluated in various stress regimes, and under a wide range of vertical confinement settings replicated via the Winkler model. Results are assessed versus those from injection flow to obtain a novel holistic insight on flow-induced geomechanics. Overall, an intricate near wellbore response is revealed, suggesting reorientation of the minimum principal plane from horizontal to vertical due to: production flow in deep reservoirs where the confining stiffness parameter exceeds that of the target layer; injection flow where the stiffness of the target zone exceeds the confining stiffness (typical in shallow reservoirs, or reservoirs subjected to prolonged injection cycles). Dominant failure mechanisms due to injection and production are shear and pore collapse, respectively. Results suggest generation of shear failure under production flow, where the confining stiffness differs from the stiffness of the reservoir formation. This hypothesis is more prone to occur in geologic formations with lower friction angle.