Geomechanical Evaluation of Thermal Impact of Injected CO2 Temperature on a Geological Reservoir: Application to the FutureGen 2.0 Site

The impact of temperature variations of injected CO2 on the mechanical integrity of a reservoir is a problem rarely addressed in the design of a CO2 storage site. The geomechanical simulation of the FutureGen 2.0 storage site presented here takes into account the complete modeling of heat exchange between the environment and CO2 during its transport in the pipeline and injection well before reaching the reservoir, as well as its interaction with the reservoir host rock. An ad-hoc program was developed to model CO2 transport from the power plant to the reservoir and an approach coupling PNNL STOMP-CO2 multiphase flow simulator and ABAQUS® has been developed for the reservoir model which is fully three-dimensional with four horizontal wells and variable layer thickness. The Mohr-Coulomb fracture criterion has been employed, where hydraulic fracture was predicted to occur at an integration point if the fluid pressure at the point exceeded the least compressive principal stress. Evaluation of the results shows that the fracture criterion has not been verified at any node and time step for the CO2 temperature range predicted at the top of the injection zone.