Integrated Geophysical Exploration Methods at European Sites--Results from the I-GET Project

Abstract

The detection of fluid-bearing fractures suitable for an economic exploitation of a potential reservoir in conventional geothermal as well as in blind systems prior to drilling is the most important task in geothermal exploration. The way this task was tackled within the European I-GET project was by integrating several different geophysical methods into one final reservoir model. For this project data were actively acquired in field experiments at four European geothermal systems with different geological and thermodynamic reservoir characteristics: two high enthalpy (metamorphic and volcanic rocks), and two low enthalpy geothermal system in sedimentary rocks. The emphasis was on electromagnetic methods, mainly MT, and on either passive or active surveys at the different field sites. Existing well logs were used where available to constrain the interpretations derived from the field data. In addition, petrophysical properties of the investigated rocks have been defined by laboratory measurements. With respect to the high enthalpy sites elastic and electric rock properties have been determined at the steam/liquid transition of the pore fillings. The results of the project were presented at a final conference held At Potsdam, Germany in February 2009. A special volume on the project is in preparation in the journal Geothermics, to be published late 2009.