  A discretely fractured reservoir has the capability to support and sustain
long term geothermal energy extraction operations. The process of injecting
cold water to extract hot water from a fracture reservoir results in thermal
and poroelastic stresses in the rock matrix. Therefore, these
thermo-hydro-mechanical (THM) mechanisms govern the efficiency of an enhanced
geothermal system (EGS) operation. However, THM mechanisms are governed by
various rock and fluid parameters as well as on the initial and boundary
conditions of the model set-up. In this paper, we have identified and analyzed
22 such parameters. Due to this large number of involved parameters, it is
difficult to accurately estimate the relative importance of individual
parameters. To address this issue, we have performed an extensive sensitivity
analysis for the purpose of the Horizon 2020 project, Multidisciplinary and
multi-contact demonstration of EGS exploration and Exploitation Techniques and
potentials (H2020 MEET) using the design of the experiment method and
identified key parameters influencing three key outcomes of the simulation:
thermal breakthrough time, mass flux, and overall energy recovery. We found
that for a given discrete fracture network, the fracture aperture, the rock
matrix permeability, and the wellbore radius are the most influential
parameters controlling the thermal breakthrough time, mass flux, and overall
energy recovery.
