**1. Introduction**

Past storage pilot projects and enhanced oil recovery efforts have shown that, geologic sequestration of CO2 is a technically viable means of reducing anthropogenic emission of CO2 from accumulating in the atmosphere [1,2,3]. Security of storage is one of the most important concerns with the long term injection of CO2 in underground formations. Injection of CO2 induces stress and pore pressure changes which could eventually lead to the formation or reactivation of fracture networks and/or shear failure which could potentially provide pathways for CO2 leakage through previously impermeable rocks [4]. Therefore geomechan‐ ical modeling plays a very important role in risk assessment of geological storage of CO2.

In order to determine whether the induced stress changes compromises the ability of the formation to act as an effective storage unit, a geomechanical assessment of the formation integrity must be carried out. In our previous work, we have studied the dynamic propagation of fracture in the Rose Run sandstone reservoir in Ohio River valley under isothermal [5] and thermal condition [6] for injection above fracture pressure. In this paper, the thermal effect of injection on the possibility of tensile and shear failure in the reservoir and caprock are studied for injection below fracture pressure. This study utilized a fully coupled reservoir flow and geomechanical model which allows accounting for poroelastic and thermoelastic effects and can model static and/or dynamic fractures.

To examine the possibility of shear failure in the caprock, Mohr-Coloumb Criteria was used.
