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Defining, exploring, imaging and assessing reservoirs for potential heat exchange - Potsdam, Germany, Workshop1
Defining, exploring, imaging and assessing reservoirs for potential heat exchange - Potsdam, Germany, Workshop1
6-8 November 2006 GeoForschungsZentrum Potsdam (GFZ)
email support
Magnetotelluric sounding of the geothermal zones enables constructing 3-D electric 
resistivity model of the studied area, mapping the geothermal reservoir and 
monitoring its macro-parameters. Spichak (1999, 2002) applied Bayesian inversion of 
MT data in order to construct 3-D resistivity model of the Minamikayabe geothermal 
zone (Hokkaido, Japan). It was found, in particular, that rather thin highly 
conductive layers attributed to the clay cap (with resistivity values not exceeding 
6 Ohm.m) cluster in the southern part of the studied area and their horizontal 
dimensions at first increase with depth, reaching a maximum in the depth range from 
about 200 to 800 m, and then decrease again.
Spichak (2001) has found the most suitable data transforms for adequate 
interpretation of MT measurements carried out with the purpose of monitoring 
variations in the geothermal reservoir resistivity with temperature. It was also 
shown that the conductive channel (for instance, fluid filled fault) connecting the 
reservoir with the surface strengthens the effect of the resistivity variation 
inside the reservoir. Firstly, it increases the diameter of the zone for reliable 
monitoring, and, secondly, reduces the period threshold sufficient for detection of 
even small variations of the electrical resistivity.
Spichak and Popova (2000) developed an Artificial Neural Network (ANN) expert 
system for detection of 3-D fault macro-parameters from MT data. Using this system 
enables not only to get an idea about the fault location but also to monitor the 
fluid circulation manifested in its electric resistivity variation.    
Accurate interpretation of magnetotelluric data in the presence of near-surface 
geological noise is still an unresolved problem. In order to overcome this 
difficulty Spichak (2001) proposed a technique based on the upward analytical 
continuation of the anomalous MT field to the reference plane located 200-500 m 
higher than the top topographic point by means of the integral transformations. 
This allows not only to filter the data that is necessary for proper imaging, but 
also to reduce the data to a “common denominator” in the case of their collection 
over the relief surface.
Finally, Spichak et al. (2006) have proposed the method of indirect temperature 
estimations from MT measurements in the geothermal areas. Practical application of 
this method enables, first, to decrease the temperature uncertainty range when the 
amount of temperature logs available is insufficient; second, to perform more 
precise temperature estimates in extrapolation mode; third, to monitor the well 
temperature basing on surface observations of MT field and, at last, to carry out 
remote temperature assessment in wells at depths with extreme conditions unsuitable 
for available geothermometers.
The study was supported by RFBR grants (05-05-08013 and 07-05-00017) and INTAS 
grant 03-51-3327.   


Spichak, V.V., 1999. Magnetotelluric fields in three-dimensional geoelectric models 
(in Russian). Scientific World, Moscow, 204pp.  
Spichak, V.V., 2001. Three-dimensional interpretation of MT data in volcanic 
environments (computer simulation). Annali di Geofisica 44 (2), 273-286.
Spichak, V.V., 2002. Advanced three-dimensional interpretation technologies applied 
to the MT data in the Minamikayabe thermal area (Hokkaido, Japan). Expanded abstr. 
EAGE 64th Conference, Florence, Italy.  
Spichak, V.V., and Popova, I.V., 2000. Artificial neural network inversion of MT - 
data in terms of 3D earth macro – parameters. Geoph. J. Int. 42, 15-26.
.Spichak, V.V., Zakharova, O.K., Rybin, A.K., 2006. On the possibility of the 
indirect electromagnetic geothermometer. Dokl. Russian Akad. Sci. (in Russian) (in 
Id: 41
Place: GeoForschungsZentrum Potsdam (GFZ)
14473 Potsdam, Telegrafenberg
Starting date:
07-Nov-2006   10:50
Duration: 03'
Contribution type: Poster
Primary Authors: Prof. SPICHAK, Viacheslav (Geoelectromagnetic Research Center IPE RAS)
Presenters: Prof. SPICHAK, Viacheslav
Material: slides Slides
poster Poster

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