Review of the results presented in WGC2005 concerning the investigation of Enhanced Geothermal Systems by D. Mendrinos and Dr. C. Karytsas Centre for Renewable Energy Sources February 2006

Geophysical Investigation Hydrothermal Systems Hydrothermal Systems  Enhanced Geothermal Systems  Enhanced Geothermal Systems

Exploration Resistivity Resistivity  21 papers Heat Flow Heat Flow  10 papers Gravity Gravity  2 papers Reflection Seismics Reflection Seismics  2 papers Porosity Porosity  2 papers

Rocks Resistivity DC resistivity (Schlumberger, etc.) DC resistivity (Schlumberger, etc.)  1-D Inversion  1-D Inversion (2 papers)  3-D Inversion  3-D Inversion (3 papers) Magneto-Telluric (MT) Magneto-Telluric (MT)  1-D Inversion  1-D Inversion (6 papers)  2-D Inversion  2-D Inversion (5 papers)  3-D Inversion  3-D Inversion (4 papers)  CSMT  1-D Inversion  CSMT  1-D Inversion (1 paper) Core-Sampling Core-Sampling  laboratory measurements  laboratory measurements (1 paper)

Earth Heat Flow Borehole Temperature Borehole Temperature  4 papers Thermal Manifestations Flow Rate Thermal Manifestations Flow Rate  3 papers Earthquakes Earthquakes  2 papers Airborne Gamma Ray Airborne Gamma Ray  1 papers Airborne Magnetic Airborne Magnetic  1 papers

Production Micro-Seismic Activity Micro-Seismic Activity  4 papers Micro-Gravity Transients Micro-Gravity Transients  3 papers Temperature Transients Temperature Transients  1 paper SP Transients SP Transients   1 paper

PNOC Experience, Philippines Period: Schlumberger Resistivity Schlumberger Resistivity  shallow current penetration  smectite cap-rock (~10 Ohm.m)  manifestations of deeper reservoirs  1000 MWe

PNOC Experience, Philippines Period: MT, 1-D Inversion MT, 1-D Inversion  deeper current penetration ( 2 km)  geothermal reservoir ( Ohm.m)  enhanced geothermal systems  2000 MWe

ENEL Experience, Italy Reflection Seismics Reflection Seismics  Major fault zones  ~ 4 km depth  700 MWe

MT, 3-D Inversion Excellent imaging down to 2-3 km Excellent imaging down to 2-3 km  Need for noise filtering at low frequencies Sophisticated algorithms Sophisticated algorithms  Demanding computing equipment Interpretation: Interpretation:  Better starting point for the Earth Scientist  Correlation with drilling & other data