Numerical analysis of stress path evolution in the overburden of depleting reservoirs: a parametric study

Abstract Pore pressure changes during hydrocarbon extraction from geological reservoirs or CO 2 injection into a reservoir lead to significant stress changes in the reservoir and surrounding rock. Such stress changes can be described by stress path. This work aims to understand the factors influencing stress paths in the overburden above depleting reservoirs by conducting a parametric study using numerical simulations. The geometry of the reservoir, particularly its aspect ratio, significantly affects stress changes in reservoir surroundings, especially in regions proximate to the reservoir. While reservoir depth generally has a minor impact on stress paths, it becomes more important in shallow and wide reservoirs that are impacted by the free surface. Additionally, stiffness contrast between the reservoir and its surroundings, both isotropic and anisotropic, significantly influences stress arching. Our numerical simulations for linear elastic scenarios exhibit linear trends in stress path dependence of principal stresses. Using these trends, we developed an analytical approximation to predict stress paths for considering non-linear inelastic material behavior. Understanding which factors impact subsurface stress alterations is important for both monitoring of petroleum-related production and long-term CO 2 storage.