WP3 - State-of-the-Art

Objectives: Within SURE, different technologies to enhance a geothermal system (EGS) will be discussed. The goal of this workpackage is to provide a matrix of different stimulation treatment technologies on the one hand and their related benefits and risks in different geothermal settings on the other hand. A special focus will be on the benefits and drawbacks of the water jet drilling technology in comparison to the more established stimulation treatments. The following issues will be considered:

  • Flow performance of the well prior to and after the stimulation
  • Induced seismicity
  • Chemicals used
  • Sustainability/life time of the stimulated system in terms of the thermal breakthrough
  • Sustainability/life time of the stimulated in terms of sustainable hydraulic properties
  • Environmental footprint of the necessary technical equipment for the stimulation treatment
  • Necessary time and budget to perform an operation

As the possible length of the drilled laterals is currently limited to approximately 100 m, the RJD technology has a  potential  benefit  in  highly  heterogeneous  reservoirs,  where  strong  and  eventually  even  anisotropic  permeability variations can be observed in the vicinity of the main bore. These can be either fracture, fault or karst systems not connected to the main bore or highly permeable matrix structures as can be found, for example in channel structures in sandstones. Based on these assumptions, geothermal sites and the corresponding reservoir rock types will be selected for further investigation in WP4-7.