Electromagnetic tomography of the geothermal zones
- Key words
- Electromagnetic tomography, magnetotelluric sounding, three-dimensional mapping, geothermal r
- Location
- Minamikayabe, Japan
- Conference
- International Geothermal Workshop, Russia
- Year
- 2003
- Session
- Exploration and modeling of geothermal reservoirs and drilli
- Language
- English
- Paper number
- W00042
Full text
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Abstract
The thermal horizons have very small electrical resistivity in comparison with the host rocks. This gives grounds to use electromagnetic methods for their remote spatial localization. EM methods enable not only to determine the location of the geothermal reservoirs but also to construct their three-dimensional models without drilling wells. Such models, in turn, serve as a reliable basement for estimation of the geothermal potential during the exploitation phase and, correspondingly, for more precise prediction of the reservoirís life-in-service.
In order to map the geothermal reservoir and to monitor its boundaries from the earth surface the magnetotelluric sounding method is suggested. It is based on the registration on the earth surface of the electromagnetic field, induced in the earth by natural sources. Such measurements provided over the network of sites enable to construct three-dimensional model of the reservoir, which could be used for estimations mentioned above [1, 2]. It is important to note that regular magnetotelluric sounding supplemented by geophysical information available from the drilled wells allow to carry out a remote spatial monitoring of the thermal waters, which significantly increases the effectiveness of the geothermal plant operation.
[1] Spichak V.V., 1999. Magnetotelluric Fields in 3-D Geoelectric Models: Scientific World, Moscow. 204 (in Russian).
[2] Spichak, V.V. Advanced three ñ dimensional interpretation technologies applied to the MT data in the Minamikayabe thermal area (Hokkaido, Japan) // Ext. Abstr. 64th EAGE Conference, Florence, Italy. 2002.
Abstract file
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