Karlsruhe Institute of Technology, Germany
This presentation aims to introduce a filtering concept for evaluation and optimization of the feasibility and energy productivity for hydrothermal doublet systems. It also provides an intensive parametric study for several constraining geological- and engineering-related parameters which are selected based on limited available data at an early stage of geothermal projects. A new code, called TIGER, is introduced for modelling coupled thermal-hydro processes in porous media. Two reservoir conditions are studied and compared: a) homogeneous and b) fractured
reservoirs. The effects of different fracture orientations and configurations are considered. For feasible and sustainable production over 30 years in the case of the homogeneous reservoir, reservoir permeabilities >5e-14 m2 and sufficient reservoir thickness are required. While reservoir thickness is directly proportional to reservoir performance, increasing reservoir permeability will after a certain threshold reduce reservoir performance due to thermal break-through. To improve reasonably fluid circulation, either a direct connection of wells via a common fracture or indirect connection through fractures network is necessary. However, fast thermal break-through is a common thread, especially for well distances <400 m and high transmissive fractures, and has to be considered during the design of reservoir operation. This study supplies several self-described and contourstyle charts, as guidelines, for project developers and decision-makers to initially evaluate sustainable geothermal potentials in different projects.
