Major Events/Results 1998-01

Year

Organisation

Tasks

Results
1998
  • Agreement between partners for 98-2001 programme
  • Enlargement of EEIG by EDF, ENEL, RWE, SHELL
 
  • 4. HDR International Forum, Strasbourg
  • Review of HDR technology
  • Review of HDR by EEIG
  • Preparation of the deepening of GPK2
1999  
  • Deepening of GPK2 to 5000 m (TVD)
  • Drilling through the granite from 3876 m to 5020 m within 104 days without any major problems
  • Successful completion of GPK2 with new high temperature metal packers cement
  • Successful tests of the special cement
  • Bottom hole coring, recovering of a 1.3 m core
  • Borehole logging: NGS, calliper, ARI, UBI, temperature
  • Geological investigations (cuttings, core)
  • Seismic monitoring during drilling
  • Bottomhole temperature at 5000 m TVD of 202°
  • Fractured, hydrothermalised reservoir, comparable to the shallow reservoir
  • Major conductive fracture set oriented N106E, two secondary fracture sets oriented N140E and N20E. All fracture sets are steeply dipping to the West or East.
2000  
  • Drilling a new seismic monitoring well OPS4
  • Drilling of OPS4 to a depth of 1537 m.
  • A 4-channel radio telemetry system installed on the top of a 15 m mast for transmitting the seismic signals to GPK2.
 
  • Assess the characteristics of the open hole of GPK2 prior to stimulation
  • Slug test in GPK2 indicated an undisturbed transmissivity of 0.03-0.08 Dm, which is in the similar range fomerly observed at 3800 m
  • Productivity test indicated a range of 0.01-0.03 l/bar s.
  • Low flow injection test (max. pressure 2.7 MPa) indicated an injectivity of 0.02 l/bar s. Temperature logs indicated permeable zones at 4520 m, 4770 m, 4980 m.
 
  • Stimulation of the deep reservoir at GPK2
  • Started with 800 m³ of salt-saturated brine, successfully initiation of the lower permeable zones.
  • In total 23'400 m³ water injected.
  • Flow rated from 30 l/s and 40 l/s to 50 l/s.
  • Maximum wellhead pressure reached 14.5 MPa.
  • Pressure monitoring indicated a rather impermeable reservoir outer boundary.
  • More than 31'000 microseismic events recorded, cloud aligned approx. NNW-SSE about 500 m wide, 1500 m long and 1500 m tall.
  • Geochemical analysis indicates convection cells within the stimulated reservoir.
  • Successful using of high temperature (200°C) production logging tools (PTF) in GPK2 during stimulation.
 
  • Data analysis, interpretation, modelling
  • Development of a conceptual model of an 3000-3600 m deep HDR/HFR system in the Rhine Graben
  • Development of a generalised HDR/HFR/ Graben model down to 4500-5000 m
  • Numerical modelling of stimulation and circulation processes.
2001  
  • Initiation of the Scientific Pilot Plant programme
  • Phase I (development of an underground heat exchanger ready for energy production) and phase II (infrastructure for electricity production, reservoir characterisation, economics improvment) initiated.