The Stanford Geothermal Program achieves proof of concept in the use of nanoparticles as tracers to characterize fractured rocks. The result comes from research funded by the U.S. Department of Energy in 2008 to accelerate technology development for Enhanced Geothermal Systems (EGS), a clean energy technology capable of producing baseload electricity across the United States.

Stanford had received up to $967,541 to develop wellbore tools, including a downhole enthalpy meter and reservoir engineering approaches including nanotechnology, Resistivity Computer Tomography method and nonparametric regression for fracture characterization.

This research will help developers learn more about the fracture systems in geothermal reservoirs so that they may better predict the results of reservoir simulation.

The ultimate goal of the Stanford project is to utilize the nanoparticles as sensors to characterize subsurface fractures. The initial experimentation with nanoparticle injection served as a basic milestone of this vision.

It was essential to verify the possibility of recovering the nanoparticles following their injection and to demonstrate that they were not trapped in the pore spaces by hydraulic, chemical, or electrostatic effects.

To investigate these issues, a nanofluid was created by suspending SiO2 nanoparticles in a liquid solution and then injecting the solution into a Berea sandstone core. The injected nanoparticles were transported through the pore space of the rock and were detected and recovered in the effluent.


-  Katrice Jalbuena

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Sources:

¹ http://apps1.eere.energy.gov/news/progress_alerts.cfm/pa_id=185
² http://www.eere.energy.gov/
³ http://www1.eere.energy.gov/geothermal/news_detail.html?news_id=12018
⁴ http://pangea.stanford.edu/ERE/research/geoth/index.html