Geothermal exploration using electrical methods

Abstract

Geophysical electrical methods play an important role in the study of geothermal fields. They are widely used, by virtue of large resistivity contrasts encountered in them, in almost all stages of geothermal research. The different techniques and the methodologies employed, vary according to the target sought.

In this work, initially a general review of the use of the electrical methods in geothermal exploration is given. Then a description of a typical-form geothermal field is presented and its impact to electrical parameters of the geological formations encountered in it is commented.

The basic elements of the various electrical methods are described in a short form, and their application on the specific geothermal targets is pointed out.

As an example, the Milos/Greece high-enthalpy geothermal field case history is finally presented.

In this presentation, apart from the extensive references for each topic discussed, more weight has been put on the relationbetween the various geothermal targets and the electrical methodologies applied for on one hand, while on the other hand emphasis has been put on the study of fracture zones and faults. The latest are the most important targets in geothermal research since they are considered as the most promising drilling sites for productive drillholes.