Seismoelectric effects for geothermal resources assessment and monitoring
Résumé
In the context of geothermal power plant operations, large amount of fluid is injected and circulates through the subsurface. Being able to identify pre-existing water-filled fracture networks (reservoir scale) can greatly help to (1) image and assess geothermal resources and targets, and (2) inform on and monitor stimulation successes and risk mitigation, by mapping newly activated fracture networks. Traditional seismic imaging techniques fail to resolve fluidphase properties, while purely electromagnetic approaches typically provide limited, low-resolution constraints on the rock structure. Our goal is to assess the use of seismoelectric effects (SEE), which arise from seismic-to-electromagnetic conversion in naturally charged porous media with a certain degree of fluid saturation. The key here is that, by leveraging the depth sensitivity of seismic signals, in combination with the fluid sensitivity of electromagnetic techniques, we can identify coupled seismic-EM pore-level phenomena and gain the advantages of both. In this contribution, we demonstrate the numerical implementation of SEE and highlight the existence of three type of signals. We also introduce in progress efforts of practical use of SEE for geothermal monitoring through laboratory experiments and field surveys.
Domaines
Sciences de la Terre| Origine | Fichiers produits par l'(les) auteur(s) |
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