Hydrology and Land Surface Studies
Magnetotelluric monitoring of a fluid injection: Example from an enhanced geothermal system
Article first published online: 21 SEP 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 18, September 2012
How to Cite
2012), Magnetotelluric monitoring of a fluid injection: Example from an enhanced geothermal system, Geophys. Res. Lett., 39, L18403, doi:10.1029/2012GL053080., , , and (
- Issue published online: 21 SEP 2012
- Article first published online: 21 SEP 2012
- Manuscript Accepted: 13 AUG 2012
- Manuscript Received: 12 JUL 2012
- phase tensor
 Enhanced geothermal systems (EGS) are on the verge of becoming commercially viable for power production, where advancements in subsurface characterization are imperative to develop EGS into a competitive industry. Theory of an EGS is simple, pump fluids into thermally enhanced lithology and extract the hot fluids to produce energy. One significant complication in EGS development is estimating where injected fluids flow in the subsurface. Micro-seismic surveys can provide information about where fractures opened, but not fracture connectivity nor fluid inclusion. Electromagnetic methods are sensitive to conductivity contrasts and can be used as a supplementary tool to delineate reservoir boundaries. In July, 2011, an injection test for a 3.6 km deep EGS at Paralana, South Australia was continuously monitored by both micro-seismic and magnetotellurics (MT). Presented are the first results from continuous MT measurements suggesting transient variations in subsurface conductivity structure generated from the introduction of fluids at depth can be measured. Furthermore, phase tensor representation of the time dependent MT response suggests fluids migrated in a NE direction from the injection well. Results from this experiment supports the extension of MT to a monitoring tool for not only EGS but other hydraulic stimulations.