Thermal stresses around egs

Developing an Enhanced Geothermal System (EGS), is a complex process and is dependent on range of design parameters, geological and operating variables. Stresses around EGS are believed to be either 'sound and non-harming' or 'violent and catastrophic' among different groups involved, directly or indirectly, in EGS. This paper explains how thermal inflow from country rock to the reservoir rock induces temperature changes in the zone, herein referred to as "impact zone", around the reservoir. The growth behavior of impact zone depends on aforementioned sets of variables and is explained in this paper. Thermal stresses are generated during and after working cycle of the EGS within this impact zone due to thermal changes. This paper also gives an insight in understanding the behavior of stresses distribution around reservoir rock. As the reservoir rock is thermo-elastically connected to the country rock, newly generated stresses interact with the existing in-situ stresses under prevailing conditions of geological, design and operating variables. A simple model has been used for the demonstration of facts stated in this paper. Later on, variables dictating the continuous, safe and efficient working of EGS are also outlined.