Objectives and problems to be solved :
The Hot Dry Rock (HDR) / Hot Fractured Rock (HFR) concept aims to utilize the vast amount of heat stored in the Earth's crust but which is not accessible by conventional geothermal technology. In HDR/HFR systems, a well is drilled into high-temperature (typically >180 oC) fractured basement rock that underlies most of Europe and stimulated to enhance the natural permeability of the fracture network to create a reservoir or heat exchanger into which additional wells are drilled. Water circulated through the fracture network in the hot rock via the wells gathers heat, which can be extracted at the surface to generate electricity or for direct use. A recent 4-month circulation test between two wells at the Soultz site has demonstrated a substantial increase in the transmissivity of fluid between wells after hydraulic stimulation without any water losses or adverse environmental impact. Tracer and hydraulic tests suggest the existence of a subsurface heat exchanger with dimensions of hundreds of meters at a depth of 2900 to 3500 m. The most recent activity was a successful drilling campaign to deepen one well to 5000 m into igneous rock with a temperature of over 200 oC and a stimulation test that created a new reservoir at this depth. This 3-year stage of European HDR/HFR research programme at Soultz is the first phase in the construction and testing of the Scientific Pilot Plant.
Description of work:
The first phase in the construction of the pilot plant centres on design and installation of a three-well module that comprises one injector and two production wells, and on the creation of the reservoir and heat exchanger by stimulating the three wells. Each stimulation creates one of three parts of the reservoir/heat exchanger. Work package 1 comprises a large hydraulic stimulation of the well already existing on site. Work package 2 centres on drilling a deviated deep well to a depth of around 5000 m for re-injection of produced geothermal brine. The bottom of the injection well will be around 600 m apart from the bottom of the existing production well. Work package 3 features the very large stimulation of the injection well. At this point, an independent panel will review the results of the stimulation and confirm the next steps of the work programme. The tasks related to the drilling of the second production well (work package 4) are similar to those described in work package 2. Work package 5 consists of the large stimulation of the second production well and a short term/low rate circulation test to estimate the facilities necessary for a later long-term circulation test. The cost-result analysis will provide a benchmark for the unit technical cost of subsurface operations for future prototypes. Technology development (drilling, completion, logging, stimulation and reservoir modelling) forms the core of work packages 6 to 8. Data management is the theme of work package 9, and a generic classification of Europe's HDR/HFR reserves with a possible strategy for their development are mapped out in work packages 10 and 11. Another work package comprises co ordination, financial, administrative, operational and scientific management for design, subcontracting and supervision of all work packages by the EEIG Resident Team. Expected results and exploitation It is expected that this work will demonstrate that all the means are in place to sustain a long-term circulation of 70-100 kg/s of water at T>180°C. In the subsequent phase, this circulation will be tested and used to supply up to four 1.5 MWe generating units.
Funding SchemeCSC - Cost-sharing contracts
77339 Kingwood, Texas
72547 Bad Urach