Quantum Dot Tracers for Use in Engineered Geothermal Systems Geothermal Project

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Last modified on July 22, 2011.

Project Title Quantum Dot Tracers for Use in Engineered Geothermal Systems
Project Type / Topic 1 Recovery Act: Enhanced Geothermal Systems Component Research and Development/Analysis
Project Type / Topic 2 Tracers and Tracer Interpretation
Project Description Quantum dots offer great potential for use as both conservative and reactive tracers for EGS applications. Not only do these colloidal nanoparticles possess all of the qualities of the naphthalene sulfonates (detectability, thermal stability, nontoxicity and affordability), they can be made to fluoresce in the visible and near infrared regions of the spectrum, which renders them much more practical for field analysis. More importantly, their surface chemistries can be modified with compounds that sorb in a predictable manner with rock (fracture) surfaces. And, whereas the quantum dot cores promise excellent thermal stability, their surface chemistries can be modified with compounds that thermally decompose at appropriate temperatures, thereby allowing them to drop out of solution—again in a quantifiable manner. Also, and perhaps most importantly, the diameters of the nanoparticles can be modified, thus allowing for their diffusivities to be varied over a large range.
State Utah
Objectives Develop and demonstrate a new class of tracers that offer great promise for use in characterizing fracture networks in EGS reservoirs.
Awardees (Company / Institution) University of Utah
Awardee Website http://www.egi.utah.edu/
Partner 1 Los Alamos National Laboratory
Partner 2 AltaRock Energy Corporation

Funding Opportunity Announcement DE-FOA-0000075
DOE Funding Level (total award amount) $768,059.00
Awardee Cost Share $470,439.00
Total Project Cost $1,238,498.00

Principal Investigator(s) Peter Rose, University of Utah
Other Principal Investigators Michael Bartl, University of Utah; Paul Reimus, Los Alamos National Laboratory; and Susan Petty ,AltaRock Energy
Targets / Milestones - Systematically design, fabricate, and test quantum dot tracers under controlled laboratory and field conditions.

- Design and fabricate highly luminescent, nonsorbing quantum dot tracers. - Add silica-glass layers of varying thicknesses that will both protect the fluorescent cores and allow for variation in diffusivity.
- Modify their surfaces to render them reversibly sorptive.
- After the fabrication, characterize their thermal stability in autoclave experiments and study their fluorescence, flow, diffusivity, and sorption properties in high temperature flow reactors.
- Develop and calibrate numerical models with laboratory data in order to calculate fracture surface areas adjacent to an EGS wellbore based upon the physical behavior of the various quantum dot tracer families.
- Conduct injection/backflow experiments in EGS wellbores using the nanoparticle tracers and use the numerical model to calculate near-wellbore fracture surface areas.

Location of Project Salt Lake City, UT, Los Alamos, NM

Impacts If successful, the new tracers could determine important heat exchange parameters such as fracture surface area and average fracture aperature.
Funding Source American Recovery and Reinvestment Act of 2009
References EERE Geothermal Technologies Programs[1]


  1. EERE Geothermal Technologies Programs