Modeling CO2 storage Using Coupled Reservoir-Geomechanical Analysis

T.I. Bjørnarå, F. Cuisiat, E. Aker, and E. Skurtveit
Norwegian Geotechnical Institute(NGI), Oslo, Norway

The geomechanical effects related to CO2 injection into the Krechba formation at In Salah, Algeria, are considered through a coupled modeling approach to simulate simultaneously CO2 migration in the aquifer and the surrounding formations, as well as the poro-elastic stress changes occurring during injection. The model is based on the simultaneous resolution of the governing equations for two-phase fluid flow in porous medium and poro-elasticity. CO2 from the produced oil and gas is re-injected into the ground as part of a CO2 storage demonstration project where one of the main goals is to verify long-term storage capacity from short-term monitoring. A significant heave at the injection sites is observed and a 3D FEM model is defined using COMSOL Multiphysics to verify it. The high observed uplift of the surface above the injection site is supported by simulations.