Presentation - UC Davis Geology

Identifying Blind Geothermal Systems through
Integrated Geologic, Geochemical,
and Geophysical Studies
James Faulds, UNR
Nevada Bureau of Mines & Geology
• Basin and Range – Region of high heat flow
• Ironic that what little water region has is hot
• Difficult to find sufficient fluid flow
• Permeability more important than temperature
• Most geothermal resources are blind
• Need multi-disciplinary studies to discover new
resources
Desert Peak – Blind System

Challenges, Barriers, and Needs
• Current technology cannot identify best
geothermal sites with a high degree of
certainty without drilling.
– Permeability
– Temperature
• Drilling is expensive and generally has high
risks.
• Inadequate knowledge precludes low-risk
options to effectively select sites and
characterize their physical parameters as
potential geothermal reservoirs before
drilling.
• Better characterization of known systems
needed to address these problems.
• Our approach – Characterize settings
favorable for geothermal activity and develop
more comprehensive, conceptual models that
can facilitate exploration.
Beowawe
Fly Ranch Geyser – Blind system

Exploration Challenges
• Exploration Challenges
– Spring directly above upflow from
deep source (uncommon)
– Outflow from source (common)
– Hidden or blind systems (most
common)
• Results – significant drilling risk
– Hot dry wells
– Overturn in down-hole temperatures
• Need better conceptual models to:
– Locate areas of upflow
– Avoid typically less productive
outflow zones
Non-Productive Well
Blue Mt., Nevada
Productive Well
Productive wells commonly proximal
to non-productive wells
Productive
Non-Productive Well
Productive Well
Non-Productive
Non-Productive
Desert Peak, Nevada
From Richards and
Blackwell, 2002

Project Goals
Gravity Data
Geologic-Structural Data
• Identify multi-faceted characteristic
signature of known, high-enthalpy,
productive geothermal systems based
on several methods and techniques:
– Structural geology and geologic maps
– Gravity
– Seismic reflection-refraction
– Magnetotellurics (MT)
– Soil gas flux
– Geochemistry
• Integrate data into one geodatabase
• Generate 3D models of systems
Magnetotelluric Data
Seismic Reflection Data
3D Model

Project Objectives
• Determine characteristic geologic and
geophysical signature for productive
geothermal systems
• Relate these findings to tectonic setting
and regional strain rates
• Later apply these methods in a Phase
II to discovering blind geothermal
systems
– Estimates suggest that ~3/4 of systems in
Great Basin region are blind or hidden
– Example below from Hot Springs Mts, NW
Nevada – 2 of 3 high-temp systems blind
Structural Settings of Geothermal
Systems (Faulds et al., 2013)

Approach
• Review all available data sets for several
operating geothermal systems in
different structural settings
• Integrate geologic, geophysical, and
geochemical data from productive
geothermal fields in Great Basin region,
(e.g., systems with existing power plants):
– Dixie Valley
– Steamboat
– Desert Peak
• Phase I relies on existing data due to
limited funding for data acquisition and
is collaborative with industry at these
sites
• Very limited new data acquisition
possible in some areas
• Variety of settings selected for study to
best characterize range of values for
productive systems

• Integrated geodatabases
contributed to NGDS.
• Descriptions of characteristic
signatures.
• Final report.
Outcome/Deliverables
• Peer-reviewed published paper.
Steamboat, Reno

Impact
• Project has potential of making critical
breakthroughs
– Identifying characteristic signatures of
geothermal systems
– Developing techniques for identifying blind
geothermal systems
• May significantly expand the overall
geothermal potential of the Great Basin
• May lower costs of geothermal development
• May foster economic development in rural
areas
• Project will help educate next generation of
geothermal geoscientists
Strain rates reflect the
second invariant strain
rate tensor (10 -9 /yr)
Faulds et al. (2012)
Fairway 3D Mapping of Geothermal System
(Siler and Faulds, in press)

Project Duration/Proposed Budget
• Project duration – October 1, 2013
to September 30, 2014.
• Proposed Budget - $59,990
– Non state-funded faculty salaries - $11,000
– Graduate student salaries - $30,000
– Fringe – $8,240
– Travel - $2,750
– Operating - $2,000
– Overhead (10%) - $6,000
Neal Hot Springs, Oregon
Temperature Anomaly,
Desert Peak, NV

Questions?
Please fill out Level of Interest Evaluation Form (L.I.F.E.)
Roosevelt, Utah