Geothermal reservoirs are characterized by high temperature and permeability, usually leading to high resistivities. However, extensive clay alteration of the enclosing rocks results in low resistivities. The contrast of resistivity provides an excellent tool for identifying geothermal targets. Magnetotellurics is the standard method for mapping the alteration cap and, via 3D inversion, the underlying reservoir.
Geosystem has carried out geophysical surveys and interpreted the data on the majority of the world's geothermal prospects. Typically, these have been programs which have integrated MT, TDEM, and gravity data with available geochemical and geological data.
In the production stage, Geosystem specializes in microearthquake monitoring (MEQ) tecnologies to monitor the growth and development of hydraulic microfractures in the reservoir. The depletion of the steam resources is assessed by means of repeated microgravity and seismic tomography surveys.

 

Clients include:
Bali Energy, California Energy Indonesia, California Energy Commission, Amoseas (now Chevron-Texaco), LAGEO, CFE, EDA-Azores, ENAP-Chile, ENEL Green Power, Fronteer Geosciences, Geothermex, ICE, Polaris Energy, Mighty River Power-New Zealand, INDE-Guatemala, INECEL-Ecuador, IRHE-Panama, JGI, Karaha Bodas, Kenya Power & Light, PB Power-New Zealand, Pertamina, PNOC, PPC-Greece, Region Reunion, SKM-New Zealand, UNOCAL Geothermal.