Nevada Petroleum Society, Reno

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Nevada Petroleum Society, Reno September 8, 2005
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Objectives

• The Great Basin Center for Geothermal Energy
  (GBCGE) is conducting work encompassing two main
  tasks.
• (1) Outreach web pages of data and maps
• stakeholder workshops
  and
• (2) Research peer-reviewed geothermal research
  with the goal of increasing production and
  utilization of geothermal energy in the Great
  Basin.

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Blewitt GPS Project

• Regional network of 60 GPS stations came on line
  January 29, 2004
• Goal is to identify regions of high
  transtensional strain accumulation in the Earth's
  crust
• Demonstrated strain to be correlated with
  geothermal resources in the Great Basin
• Resolving sub-millimeter per year relative
  velocities between GPS stations

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Crustal Extension as Estimated from GPS Velocity
Measurements and Quaternary Fault Slip
Rates (converted to strain rate)

• Extension focused along margins of Great Basin
• Extension correlates with locations of geothermal
  power plants

magma heated geothermal systems
extensional geothermal systems
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Calvin/Kratt Remote Sensing

• ? Analyzed high-resolution airborne coverages to
  find past geothermal centers and fault zone
  extensions.
• ? Established mineral and thermal markers at
  known sites and extrapolated to unexplored areas.
  
• ? Detected previously unmapped sinter outcrops
• ? Recognized structurally controlled carbonate
  deposition that coincides with sinter outcrops
  and suggests and extension of the Bradys Fault

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Coolbaugh - GIS

• Interactive web site
• http//www.unr.edu/geothermal/interactive_maps.htm
  
• Digital Field Mapping
• Estimation of Undiscovered Resources
• Geothermal Potential Map
• Regional Structural Model (collaboration with
  Faulds, Blewitt, Henry)

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Digital Field Mapping Program Objectives 1)
increase mapping efficiency 2) increase detail,
accuracy 3) improve structural picture
Bradys Hot Spring features --- 3 days with GPS
unit
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Predicted Crustal Density of Undiscovered
Geothermal Resources
A GIS analysis synthesizes all information and
reveals new targets for geothermal
production. Circles are known economic and
subeconomic geothermal systems. Several areas
with relatively high potential for undiscovered
geothermal systems are highlighted
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Faulds Geologic Mapping

• Characterize links between geothermal aquifers
  and stratigraphic-structural features
• Better define boundaries of geothermal reservoirs
• Preliminary 3D modeling and visualization of
  fields
• Facilitate ongoing EGS study and energy
  production
• Characterize structural controls on geothermal
  systems in the northwestern Great Basin through
  integrated geologic and geophysical analyses.

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Bradys Geothermal Power Plant
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Gravity Modeling of Cross Section
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Desert Peak Thermal Plume
Localized along Rhyolite Ridge fault zone High
fracture density in step-overs provide conduits
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Oppliger InSAR

• 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 deformation.
• Detecting production induced deformation
  improving reservoir characterization management

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Bradys-Desert Peak Satellite Radar Interferometry
Geothermal Reservoir Characterization Dr. Gary
Oppliger and Dr. Mark Coolbaugh
Displacement patterns over 4.9 years Nov. 4,
1995 to Sept. 24, 2000. Each color represents
0.17 cm radar line-of-sight (LOS) distance change
to the surface. A full cycle of 16 colors
represents 2.83 cm LOS (3.07 cm vertical
displacement equivalent). A maximum of about 7 cm
LOS surface change occurred over the period, with
approximately 2.5 cm inflation from injection
just NE of the end of Brady Fault.
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Bradys-Desert Peak Geothermal FieldVertical
Surface Displacement from InSAR
Plan map showing the Jan. 1997 to Sept. 2002
InSAR anomaly contoured at 10 mm intervals. 85
mm maximum. The InSAR line-of-sight deformation
has been transformed to vertical deformation in
mm and filtered to remove signal from features
with wavelengths less than 120 meters.
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Bradys-Desert Peak Geothermal Field Reservoir
Volume Strain Modeling

• InSAR compatible volume-strain rate model for the
  Bradys and Desert Peak fields during the 5.7
  year period from Jan. 1997 to Sept. 2002.
• The Bradys field anomaly is robustly resolved in
  the data, but the Desert Peak anomaly is too weak
  to yield reliably reservoir geometry details.
• Significant volume-strain is occurring in the
  area somewhere between the surface and about 1.5
  kilometers depth.
• The elastic model employs a Poissons ratio of
  0.25.

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Louie Crustal Geophysics

• Continued implementation of a regional database
  of crustal geophysical controls on geothermal
  resource assessment
• New seismic survey of the Great Basin

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Lechler Hg Soil Gas Measurements

• Tested method at Bradys where structure is
  visible via steam vents
• Exploration for concealed structures at DP
• Geothermal applications of multi-gas geochemistry

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Mercury soil gas anomalies help identify
structural boundaries of the Desert Peak
geothermal system.
Gold wire collectors placed in the field for one
week were analyzed for sorbed Hg using a graphite
furnace AA method (Lechler, 1993)
N
Warmer colors indicate higher mercury values.
Values for each line were normalized to the line
average. Black Lines faults mapped by Faulds,
et al., 2003. Blue lines interpreted faults
based on Hg values in this study and silicified
sands mapped with hyperspectral remote sensing
(Kratt, et al., 2003. Additional faults are
likely present.
1 mile
Black circle production well Green circle
injection well Grey circle EGS site White
Polygon power plant
silicified sands
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Shevenell Fluid Geochemistry

• Geochemical sampling of thermal and non-thermal
  waters in Nevada
• Database construction, fill in gaps
• Calculate geothermometers and rank sites
• Evaluate geothermometers for Nevada thermal
  waters
• Support other projects

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Data gaps in spring chemistry and temperature
using WATSTORE and GEOTHERM From 2700
digitized springs from 7.5 Quads chemistry and
temperature of 1030 thermal springs is unknown.
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Finding Blind Systems

• A 2 m hole was dug into a playa near Salt Wells
• Water temperature 84.8ºC
• Geothermometer temperature 192ºC
• Three springs 17ºC show anomalous geothermal
  temperatures (121º - 142º).

Cold Sites
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Evaluation of Geothermometers Using Power Plant
Data
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Plot of calculations with measured Al at all
temperatures Desert Peak Reservoir
Saturation Index
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General Results

• Helped revitalize grass-roots geothermal
  exploration
• Identified new areas warranting detailed
  assessment
• Developed and demonstrated inexpensive tools for
  regional assessment
• Preliminary assessment of undiscovered resources
• Developed new remote sensing techniques to
  identify thermal anomalies at remote or
  inaccessible locations.

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Results

• Hg soil gas Identification of hidden structures
• InSAR - Detect production induced subsidence
  improved reservoir characterization management
• New 60-station GPS strain network installed and
  running since Jan 2004 2.4 Gbytes of data
  collected, and 1 mm/yr accuracy demonstrated, on
  target for basin-scale strain by summer 2006.
• GPS-Strain measurements ID exploration sites
  near BV and Fairview Peak-Rawhide
• GIS modeling independently ID exploration sites
  near BV and Fairview Peak-Rawhide

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Results

• Seismic studies ID large area of thin crust in
  Central NV partially coincident w/GIS and GPS
  anomalies
• It has been recognized that fields in the
  northwestern Great Basin are related to the
  evolving plate boundary, which is the terminus of
  shear in Walker Lane.
• Detailed analyses of well logs and core helped
  constrain the subsurface structure framework of
  DP Brady
• Remote sensing used to establish mineral and
  thermal markers at known sites and extrapolate to
  unexplored areas.

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Results

• Bulletin 91 (Thermal Waters of Nevada, by Garside
  and Schilling, 1979) revised and updated in a web
  based format chemical data and revised text
  being added
• http//nbmg.unr.edu/geothermal/gthome.htm.
• Can locate blind systems by sampling cold springs
  and playas
• Initiated work on using sophisticated software
  for construction of cross sections and 3-D models
• Successfully added significant details to
  structural models at Bradys and Salt Wells

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UNR-REC Formed(spearheaded by Allen Gates)

• New funding just received to expand the Centers
  mission!
• To be housed on the Redfield campus
• A showcase for powering, heating and cooling
  using geothermal and renewable energy

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The UNR-REC Concept

• A geothermal renewable energy public/private
  partnership
• DOE/NREL
• UCCSN (UNR, DRI, TMCC, WNCC)
• Regional Transportation Commission
• ORMAT
• Sierra Pacific Power
• Researchgeothermal renewable energy
  development and use
• Educationgraduate and undergraduate
• Outreachhydrogen production, workforce training,
  public awareness, geothermal and renewable
  energy entrepreneurship, multimedia center

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ORMAT Campus Heat Power

• Power - wholesale prices
• Circulate 180º F H2O for heating free
• Second Hi-T line for research - free
• 1 MW turbine for research - donated

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The UNR-REC Vision

• A world-class research, education, and outreach
  laboratory for the development and use of
  geothermal and renewable energy in Nevada.

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The UNR-REC Rationale

• Geothermal Renewable Energya national security
  issue

Nevadacan be a major player
Nevadaneed for economic development
GRELNPotential for significant economic,
security, and quality of life impact!
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• Sources of energy in the United States
• Oil 39
• Natural gas 24
• Coal 23
• Nuclear 8
• Hydropower 3
• Other 3
• Source The New York Times, Nov. 2003.

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UNR-REC Education

• Laboratories and equipment
• Classrooms
• Multi-media
• Internet accessible
• Examples of graduate and undergraduate education
• Power plant design and operation
• Materials science and engineering
• Hydrogen production plant design and operation
• Geothermal renewable energy development and use

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UNR-REC Outreach

• Workforce training laboratories and equipment
• Workforce training
• Hydrogen production
• Public awareness multi-media center

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Structural and Tectonic Analysis of Geothermal
Fields in the Great Basin
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Results

• Remote sensing identified previously unrecognized
  structural features and sinters at Bradys and
  helped target new drill sites.
• Applied new methods and techniques for drill core
  and cutting analysis that can rapidly map
  alteration type and degree.
• Demonstrated clear correlation between thermal
  anomalies and hydrothermal minerals at known
  production sites.