The EU funded research project I-GET is designed to develop an innovative geothermal
exploration approach based on advanced geophysical methods. I-GET contributes
directly to the ENGINE goals, research results are reported at ENGINE meetings on a
regular basis. The objective is to improve the detection, prior to drilling, of fluid
bearing zones in naturally and/or artificially fractured geothermal reservoirs. This
new approach has been tested in three European geothermal systems with different
geological and thermodynamic reservoir characteristics: two high enthalpy
(metamorphic rocks at Larderello, Travale in Italy and volcanic rocks at Hengill,
Iceland), one middle enthalpy geothermal system (deep sedimentary rocks in the
Southern Permian Basin, Gross Schönebeck/Germany), and will be applied to a low
enthalpy geothermal system (shallow sedimentary rocks at Skierniewice, Poland).
The novel aspect of the approach lies in the integration of several geophysical
methods that are commonly used independently. In the field, the most commonly used
techniques are seismic 2-D lines (relatively cheap) or 3-D grids (expensive) and
magnetotelluric recordings (relatively cheap).For I-GET, the same profile is used for
seismic and magnetotelluric recordings, complementing the structural information. The
combined interpretation and the joint inversion of these measurements has the
potential to provide more information than the sum of the two used independently.
The data were acquired in the test sites using new acquisition and processing
techniques developed to solve problems related to the particular target. The data are
compared with existing and new logs from boreholes, such that the method using
surface measurements (geophysics) will be calibrated against subsurface information.
The information provided by field measurements, well-logging and laboratory
experiments will be used to develop numerical models of the reservoirs in 3D in order
to produce a static image of the reservoirs and calculate the fluid-dynamic behaviour
of the fracture systems. The input of the results of new geophysical prospecting into
reservoir modelling will be a crucial test of the quality of the new exploration method.