University of Nevada, Reno

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University of Nevada, Reno March 25, 2004 (LBL)
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Mission

• The mission of the Great Basin Center for
  Geothermal Energy is to work in partnership with
  U. S. industry to establish geothermal energy as
  a sustainable, environmentally sound,
  economically competitive contributor to energy
  supply in the western United States.

Steamboat Springs geyser, photo Don Hudson
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Goals

• To provide needed and timely information on
  geothermal resources
• To identify and evaluate new and emerging
  technologies for geothermal assessment
• To conduct research leading to improved
  exploration for and characterization of systems
• To foster new scientific and technological
  developments
• To facilitate outreach and communication between
  geothermal energy stakeholders.

Photo Greg Arehart
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Where Does Work Fit into DOE Program

• Exploration for new geothermal areas will assist
  goal of increasing the amount of electricity
  produced from geothermal in the U.S.
• Exploration development will help expand the
  resource base and optimize resource utilization
• Finding new techniques to assess resources should
  reduce future exploration and assessment costs

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What are Work Objectives?

• Produce a web-based, stakeholder geothermal
  information system for Nevada geothermal data
• Hold informational stakeholder workshops
• Conduct an applied research program of peer
  reviewed, geothermal research addressing the goal
  of identifying and assessing geothermal resources
  to increase geothermal utilization in the Great
  Basin.

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What is the Scope of Work Through the Center?

• Characterize Geothermal Resources Understand
  Controls on Resources
• Identify Favorable Exploration Targets
• Evaluate New Geothermal Exploration and
  Assessment Technologies/Techniques (e.g., GPS,
  GIS InSAR)
• Expand on Existing Exploration and Assessment
  Techniques

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How is Work Organized?

• Center funds and coordinates nine peer-reviewed
  research projects focused on exploring for new
  geothermal areas and assessing existing ones
• One of the nine projects incorporates all data
  and results into a GIS (Coolbaugh) to model
  regional geothermal resource potential
• Oversight by Associate Director (Shevenell) and
  Director (Long)

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Who Performs Work

• Researchers at Univ. of Nevada, Reno
• Arehart Lechler
• Blewitt Louie
• Calvin Oppliger
• Coolbaugh Shevenell
• Faulds

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What has been Accomplished?

• Identified GPS geodetic measurements of strain
  rates as a geothermal exploration tool
• Identified regions with thinner than average
  crust that may have greater geothermal potential
• GIS modeling identified regionally favorable
  areas
• Buffalo Valley Fairview Peak-Rawhide

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What has been Accomplished (contd)?

• InSAR results suggest continuation of a fault
  that is currently being produced subsidence
• Digital field mapping is being demonstrated as an
  efficient means of mapping geothermal expressions
  clarifying structural controls
• Remote sensing of tufa sinter to identify
  previously unknown structures
• Regional geothermal structural database is
  identifying favorable structural environments

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What has been Accomplished (contd)?

• Significant improvements in understanding
  structural controls at DP w/integrated studies
• New detailed Geol. Map and X-Sec at DP
• New water samples collected from springs for
  geothermometer evaluation
• Considerable data are now available on the web
  and have been shared with many stakeholders

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What is Planned?

• Expanding the GPS network for better resolution
  of crustal motion in W NV
• Development of GIS predictive models for the
  Great Basin
• Focus remote sensing, GIS, GPS, chemical, and
  seismic studies on Buffalo Valley
• Evaluate influence of water table on expression
  of geothermal (local regional)
• 450-km-long seismic characterization survey is
  planned

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What is Planned (contd)?

• Additional InSAR imaging B, DP, SB
• Regional structural models for identifying
  controls on fluid flow
• Digital field mapping (Salt Wells, etc.)
• Collect samples from thermal waters with no
  available chemical data evaluate
• Complete Hg gas survey over concealed geothermal
  system
• 40/39Ar dating of young volcanic rocks
• Developing tools for predicting identifying
  critically stressed portions of the crust (new
  project)

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What are Knowledge Gaps?

• 1. Detecting concealed geothermal resources
  structures
• 2. Developing tools for predicting identifying
  critically stressed portions of the crust (new
  project) addresses EGS
• 3. The most appropriate geothermometer to use
  for particular waters/areas
• Regional structural controls are poorly
  understood
• Crustal Thicknesses

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How to Fill Knowledge Gaps

• Planned activities address specific knowledge
  gaps
• GPS, Hg soil gas, GIS modeling, remote sensing
• Detailed mapping of faults ruptures
  orientations, displacements, ages
• Spring sampling, analysis, evaluation of
  mixing/boiling processes comparison w/historical
  data
• GIS modeling elucidates regional influences on
  local structural controls detailed mapping and
  integration w/well logs, gravity data, etc.
• Regional seismic surveys

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How Would Industry Collaboration Enhance Goals?

• Greater accessibility to data to minimize
  duplication maximize integration
• Optimize exploration and development efforts
• Better understanding of structural controls
• Access to boreholes for testing
• Studies could help industry be more successful by
  helping to better understand the systems

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Current Industry Collaboration

• Ormat Desert Peak/Bradys
• Faulds, Coolbaugh, Oppliger, Calvin,
• Nevada Geothermal Salt Wells
• Coolbaugh, Shevenell, Tempel
• Presco Energy Rye Patch
• Shevenell, Tempel
• Caithness Steamboat Coso
• Coolbaugh, Sladek, Shevenell
• Numerous independents Surprise Valley,
  Tuscarora (Sulphur Springs), Hot Creek Canyon,
  Blue Mountain
• Shevenell, Garside

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Funded Projects

• Arehart, G. (34,503) - Dating of young igneous
  rocks associated with geothermal systems in the
  Great Basin.
• Blewitt, G. (149,975) - Targeting of potential
  geothermal resources in the Great Basin from
  regional to Basin scale relationships between
  geodetic strain and geological structures.
• Calvin, W. (85407) - Remote sensing for
  exploration and mapping of geothermal resources.
• Coolbaugh, M. (93,023) - Regional assessment of
  exploration potential for geothermal systems in
  the Great Basin using a geographic information
  system (GIS).
• Faulds, J. (97,760) - Geologic and geophysical
  analysis of the Desert Peak-Brady geothermal
  fields Structural controls on geothermal
  reservoirs in the Humboldt Structural Zone.
• Lechler, P. (33,984) - Exploration for concealed
  structures at Desert Peak using mercury soil gas
  detectors.

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Funded Projects

• Louie, J. (74,833) - Assembling crustal
  geophysical data for geothermal exploration in
  the western Great Basin.
• Oppliger, G. (43,056) - Investigating the
  relation between geothermal reservoir compaction,
  geometry and production rates from a ten-year
  InSAR ground displacement history at the Bradys
  and Desert Peak fields Assessing the potential
  of retrospective InSAR monitoring to assist
  reservoir management and expansion over fields
  without previously documented subsidence.
• Shevenell, L. (63,933) - Geochemical sampling of
  thermal and non-thermal waters in Nevada
  Evaluation of geothermal resources for electrical
  power generation and direct-use applications.

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Selected Data
Photo Greg Arehart
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Regional Map Showing Anomalies Identified by GPS
Survey Areas of extension thought to have
greater potential for geothermal resources
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Steamboat Hills Establishing mineral and thermal
markers at known sites and extrapolating to
unexplored areas. From Calvin Kratt, 2003
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Previously un-mapped opaline sinter
Structurally controlled carbonate
Opaline Sinter
From Calvin and Kratt, 2004
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Young Faults (NBMG/USGS)
Depth to Groundwater (NWIS)
Boron, Groundwater (NWIS)
Young Volcanics (USGS)



Quakes (NV Seismo Lab)
PZ Carbonates (NBMG)
Heat flux (SMU)
From Mark Coolbaugh, 2003
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Desert Peak Thermal Plume

• Localized along Rhyolite Ridge fault zone
• High fracture density in step overs provide
  conduits

From Faulds, 2003
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Test Hg survey at Bradys Geothermal Area From
Lechler, 2003
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Regional Geothermal Assessment Finds Crustal
Hotspot
A May 2003 survey of Great Basin geothermal
resources probed the Earths crust with seismic
waves from blasts at a large gold mine. The
survey revealed unexpectedly thin crust southwest
of Battle Mtn., Nevada, targeting a hotspot for
further assessment. A second survey scheduled for
June 2004 will test the limits of this hotspot.
From Louie, 2003
Daily excavation work at this 3-mile-wide gold
pit provided plenty of seismic energy.
Thin Hotspot
Sierra Root
NEW CRUSTAL THICKNESS MAP
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Bradys-Desert Peak Satellite Radar Interferometry
Geothermal Reservoir Characterization Dr. Gary
Oppliger and Dr. Mark Coolbaugh
Bradys subsidence feature
I-80
In December 2003, our interferograms revealed the
first large scale production related subsidence
feature reported for the Bradys geothermal field.
A first assessment of the subsidence pattern
suggests that the Bradys production zone has
strong (fault controlled?) hydrologic
conductivity along a 7 km length with a weaker
but visible extension along 11 km total. An
annual subsidence rate of 1.3 cm/year is
suggested over the central production area. The
full development of this result by our study
should materially aid management and expansion of
the Bradys geothermal field.
Bradys
Desert Peak
I-80
Figure (right) Preliminary interferogram spanning
Nov 4, 1995 to Sept 24, 2000. Each color band
represents 1.6 mm vertical change over the
interferogram period. From Oppliger, 2004
2.5 km
Preliminary image only
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Na-K-Ca Geothermometer Historical and new data,
now available at www.nbmg.unr.edu/ geothermal/gth
ome.htm From Shevenell, 2003