Simulation of CO2 injection with dynaflow
Several numerical tools aimed at improving simulation of geological storage of CO2 have been developed and incorporated into the Prévost Group’s finite element software dynaflow, which offers a modular, hierarchical approach for multiphase and multiphysics simulations. These tools allow capturing of the effects of coupling between fluid flow and thermal and geomechanical effects.
In their previous simulation of the In Salah (Algeria) injection operation, Prévost and colleagues detected the potential for thermal fracturing in the cap-rock as a result of cold CO2 injected in a reservoir at higher temperature. In 2011, the group used dynaflow to further investigate the effects of thermal stresses on wellbore and cap-rock integrity. The researchers have performed detailed analyses and parametric studies that include the effects of injection temperatures, in-situ initial stresses (in particular for a strike-slip stress regime), rock fracture toughness, friction angle and cohesion. They are in the process of assessing the risks for thermal and hydraulic fracture and shear failure.
Further work will be done to improve the compositional aspects of dynaflow, in particular in modeling boiling of CO2 as it moves from the storage formation to the surface in a leakage scenario.