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Seismoelectric Imaging Using Virtual Electrode Scanning
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 6th EAGE Saint Petersburg International Conference and Exhibition, Apr 2014, Volume 2014, p.1 - 5
Abstract
Seismoelectric scans can be used for direct mapping of the electrical and hydraulic properties of oil and gas reservoirs or acquifers. The scans involve virtual seismic electrodes which are produced by focusing acoustic energy at known positions in the subsurface and at known times. If the acoustic focus point coincides with a discontinuity in electrical and hydrological medium properties, then it generates an electric current density which leads to a difference of potential that can be observed with remote electrodes. Although seismoelectric phenomena are not new, subsurface monitoring using virtual seismic electrodes provide a huge improvement over existing methodology for two main reasons: the source of the seismoelectric conversion is localized in space, and the energy at the conversion point is maximum. The seismoelectric source behaves like a controlled electrode whose properties depend on the acoustic energy pumped into the ground and on the local medium properties. By changing the position of the focus point through appropiate time delays of the acoustic sources, we can scan the medium properties and produce a map of its properties. This map can either be used directly, or it can aid electrical tomography by increasing its resolution and robustness.