Effects of Anisotropic Poroelasticity on Stress and Pore Pressure Changes Around Subsurface Reservoirs and Storage Sites

• DOI: 10.56952/arma-2022-0694
• Publication Date: 2022-09-28T02:34:48Z
• Authors: R. M. Holt; A. Bakk; M.I. Duda; H. Yan
• Keywords: Poromechanics; Overburden; Geomechanics; Effective stress; Overburden pressure

ABSTRACT: Stresses and pore pressures change around depleting hydrocarbon reservoirs or fluid injection sites as result of reservoir pressure change. Such changes influence the stability new wells drilled may lead to fault activation, resulting in induced seismicity possibly casing damage existing wells. Forecasting requires reliable geomechanical modeling its surroundings. Classical analytical solutions are too simple, so numerical models required. The rocks surrounding often anisotropic (like overburden shale), but their elasticity is normally neglected, either because model limitations, lack input data. Here, however, impact anisotropy along with elastic contrast between undrained surroundings drained (isotropic) rock addressed through a series scenarios. It shown that isotropic unable reproduce stress predicted by models. Pore be underestimated neglecting nature poroelastic Skempton parameters. 1. INTRODUCTION Stress evolution caused depletion storage of, e.g., wastewater CO2, can handled methods, such classical theory Geertsma (1973). Although more sophisticated analytical, well exist, role computations has not been systematic manner literature. We use finite element method (FEM) simulate (shales) an reservoir. Because low permeability cap rock, shale response will remain within lifetime, unless leakage occurs faults other permeable conduits. pore-pressure ignored; they have crucial on drilling efficiency borehole during infill drilling. In accord flow out into reservoir, behavior described moduli.