**5. Conclusions**

In this paper, a roughness induced shear displacement model in a poro-thermoelastic envi‐ ronment combined with an advanced computational technique is used to study the effects of induced fluid pressure and thermal stresses (cooling effect) on reservoir permeability and consequent increase in hot water production. It has been shown that surface roughness induced shear displacement provides a more realistic prediction of residual fracture aperture. These results agree well with the experience of existing EGS trials around the world. An average increase in aperture due to fluid induced shear dilation has been found to be lower and time required to obtain a maximum stimulated volume is greater. Results of this study are in consistent with that of previous studies: for every geothermal system there exists an optimum injection schedule (injection pressure and duration). Any further increases in stimulation effort, i.e. stimulation time for a given stimulation pressure, does not provide additional permeability enhancement.
