DOE Geothermal Program Briefing

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DOE GeothermalProgram Briefing

• March 16, 2004
• Earth Sciences Division
• Lawrence Berkeley National Laboratory
• Mack Kennedy

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Geothermal Energy ProgramLawrence Berkeley
National Laboratory

• Mission Develop and integrate state of the art
  scientific methods to enhance/engineer geothermal
  systems and assist industry in finding,
  characterizing, and producing geothermal fields.
• Research Strengths
• Reservoir Engineering
• Geophysics (Seismic, EM, MT, Remote Sensing)
• Isotope Geochemistry
• Rock Mechanics
• Geology

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Lawrence Berkeley National Laboratory

• Programmatic Goals Addressed by LBNLs Geothermal
  Program
• Geothermal Resource Enhancement/Engineering
• Mechanical, thermal and chemical evolution of
  natural and induced fractures (MEQs).
• Geophysical/geochemical methods to identify
  resource expansion potential.
• Geometry and scale of fluid-matrix interaction
• Advanced numerical modeling system behavior
  under different management plans.
• Advance Fundamental Knowledge of Geothermal
  Systems
• Relationships between regional geology,
  tectonics, hydrology and formation of geothermal
  systems.
• Reduce drilling costs improved well-siting
• Optimize Resource Management
• Geochemical/geomechanical effects of injection.
• Resource response to fluid production and
  injection
• Technology Integration

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Lawrence Berkeley National Laboratory

• Collaborations
• Industry Calpine Caithness GeothermEx Unocal
  Shell Exxon-Mobil CalEnergy EMI EPDC, Japan
• Government USGS LLNL SNL INEEL
• Academic EGI, Univ. of Utah Univ. of Nevada,
  Reno UC Berkeley Stanford New Mexico Tech.
  Ohio State Univ. Southern Methodist Univ.
• Accomplishments
• Publications in Refereed Journals (2001
  Present) -- 40
• Conference Abstracts/Presentations (2001
  Present) -- 41

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Lawrence Berkeley National Laboratory

• Research Programs
• Core Research (357K)
• Detection and Mapping (223K)
• Enhanced Geothermal Systems (300K)

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Lawrence Berkeley National Laboratory

• Core Research Projects
• Geothermal Reservoir Dynamics (180K, K. Pruess)
• Isotope and Geochemical Studies (150K, M.
  Kennedy)
• Model Development and Detection of Soil Gas CO2
  Emissions (27K, C. Oldenburg, J. Lewicki)

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Core Research

• Geothermal Reservoir Dynamics
• Objective Understand coupled processes of fluid
  flow, heat transfer, and rock-fluid interactions
  (chemical, mechanical) in geothermal systems
• Develop, demonstrate, and publicly release
  TOUGHREACT code for reactive chemical transport
• Develop tracer testing approaches that can
  determine heat transfer area in EGS systems

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Geothermal Reservoir Dynamics

• Relation to Program Goals
• Improved reservoir management
• e.g. accurate and better constrained reservoir
  models for targeted water injection
• Operation of injection-production systems
• minimize detrimental effects (scaling, formation
  plugging)
• realize beneficial effects (abatement of
  deleterious chemical constituents, improved
  energy recovery).
• Characterize heat transfer properties - EGS

Effects of Fracture Spacing on BTCs for injected
tracers in vapor-dominated systems
Tracer BTCs for different diffusivities and
sorption strengths in liquid-dominated system
sorption enhances weak diffusivity tails.
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Core Research

• Isotope and Geochemical Studies
• Objective Baseline isotope and geochemical data
  sets related to exploration and reservoir
  characterization.
• Basin and Range 3He/4He Map
• Dixie Valley Integration Report
• Soil Gas CO2 Emissions
• Objective Use coupled subsurface-surface layer
  modeling to predict expected locations and
  strength of maximum surface gas concentrations
  from a sub-surface source.
• Model Development
• Detection Strategies

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Isotope and Geochemical Studies

• Relation to Program Goals
• Improved understanding of geothermal systems in
  relationship to regional geology, tectonics, heat
  flow, and hydrology.
• Expand geothermal resource base.
• Develop new geochemical methods that identify
  potential for resource expansion.

Helium isotopes unequivocal evidence for magma
(mantle) derived fluids - indication of heat
source and the role mantle melting plays in the
formation of a crustal geothermal system. Many
models of regional high heat flow anomalies in
the BR are explained by large scale underplating
of mantle derived melts. Helium isotopes can
provide constraints for these models.
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Isotope and Geochemical Studies
Helium Isotopes and Tectano-Magamtic Models
0.5-1.5 Ra
gt0.7-2.4 Ra
0.1 0.7 Ra
gt6 Ra
The positive 3He/4He spikes are associated with
major range front faults, with large
displacement, and identify zones of enhanced
fluid flow along the fault zones.
Helium Isotope Trends in the Basin and Range
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Dixie ValleyHelium Abundances and Isotopic
CompositionsEvidence for a Single Deep Fluid

• System must have at least two fluids
• Young groundwater F(4He) lt 10 R/Ra lt 0.4
• Fluid indistinguishable from geothermal
  production fluids F(4He) gt 150-200 R/Ra gt 0.8
• High ratios associated with Range Front Fault
  High permeability flow paths

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Lawrence Berkeley National Laboratory

• Detection and Mapping
• Remote Sensing of Localized Strain (32K, D.
  Vasco)
• 3-D Magnetotelluric Imaging (67K, M. Hoversten)
• Electromagnetic Imaging Methods (0K, K.H. Lee)
• Seismic Imaging (50K, E. Majer)
• Field Case Studies Review International EGS
  Studies (74K, M. Lippmann)

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Remote Sensing of Localized Strain
Synthetic Aperture Radar (SAR) reflections Dixie
Valley region.

• Program Goals
• Use satellite-based estimates of strain to
  identify potential geothermal resources
• Understand the coupled physical processes
  associated with strain localization
• Objectives
• Develop techniques and software for identifying
  geothermal targets
• Apply the methods to regions in the western US

The colors superimposed upon the reflection
image, represent phase shifts between reflections
from August 1992 to April 1996.
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Remote Sensing of Localized Strain

• Scope
• Understanding factors associated with imaging
  long term regional strain
• Understand relationship between long term
  regional strain and the emplacement of geothermal
  systems
• Organization and Personnel
• Don Vasco (LBNL) Software development, field
  application
• Bill Foxall (LLNL) - InSAR imaging,
  interpretation
• Charles Wicks (USGS) InSAR data reduction and
  processing
• Geoff Blewitt and Mark Coolbaugh, University of
  Nevada, Reno

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Remote Sensing of Localized Strain

• Accomplishments
• 2003-Use of Interferometric Synthetic Aperture
  (InSAR) data at Dixie Valley
• 2003/2004-Acquisition and utilization of point
  scatterer (PS) data for long term imaging of
  local strain. Characterization of seasonal
  changes at the mm level
• Planned for 2004-Coupled modeling of strain
  localization associated with the evolution of a
  geothermal system
• Knowledge Gaps
• Detailed (high-resolution) knowledge of regional
  strain-May be provided by InSAR data
• Factors influencing long term strain monitoring
  and the utility of PS methods for long term
  monitoring
• How strain propagates to the surface, the role of
  faults in strain localization-Addressed by
  coupled modeling
• The Role of Industry Collaboration
• Application of strain imaging methods on a larger
  scale
• Identification of promising regions for study

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Seismic Imaging

• Program Goals
• Develop state-of-the-art seismic imaging
  techniques for geothermal resource exploration
  and EGS
• Program Objectives
• Determine signatures of faults and fracture zones
  for reinterpreting existing 2-D seismic data sets
• Determine how 3-D seismic surveys can be
  optimized for pre-defined targets based on 2-D
  results
• Program Structure
• LBNLs Center for Computational Seismology by
  Roland Gritto and Ernest Majer
• Accomplishments
• Faults/Fracture zones can be identified with
  exisiting 2-D seismic data
• Distinct footprints of blind faults and fracture
  zones can be used to optimize 3-D seismic surveys
  in geothermal areas
• Knowledge Gaps
• Need to better understand the kinematics and
  dynamics of seismic wave propagation in
  geothermal areas
• Industry collaboration provides the required
  physical parameters and geometries of EGS for FD
  modeling

Rye Patch P-wave time snapshots reveals energy
attenuation, reflection and refraction by
vertical fault.
Seismogram Section
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Lawrence Berkeley National Laboratory

• Enhanced Geothermal Systems
• MEQ Monitoring at The Geysers (200K, E. Majer)
• Geochemical Study of the Effect of Fluid
  Injection at The Geysers (100K, M. Kennedy)
• Development of Fluid Injection Strategies for
  Optimizing Steam Production at The Geysers
  Geothermal Field, California (CEC-PIER Proposal,
  Submitted, M. Kennedy)

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MEQ Monitoring and Analysis at The Geysers

• Program Goals
• Provide data to improve the overall understanding
  of the relation between reservoir manipulation
  and microseimicity for the EGS program
• Objectives
• Identify parameters critical to controlling MEQ
  activity during EGS activities
• Threshold of seismicity
• Injection versus production
• Mitigate and optimize production and injection
  activities
• Scope and participants
• Extend exiting array to area of future enhanced
  injection
• Gather baseline data and monitor during
  injection
• Analyze and integrate data with injection,
  production and geochemical data
• Joint project by Calpine( M. Stark) and LBNL (E.
  Majer, M. Kennedy)

Planned MEQ array Aidlin Field, Northwest Geysers
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MEQ Monitoring and Analysis at The Geysers

• Accomplishments/Plans
• Geochemical baseline study completed, ready for
  monitoring phase
• Funded Feb 04, initial stations in place at
  Aidlin March 10
• Complete Array extension by mid- April
• Initial injection in April , main injection
  commence in Fall of 2004
• Data analysis and monitoring extend through FY
  2006
• FY 04 products
• Background seismicity and analysis WRT rest of
  The Geysers
• White paper on impact of MEQs on EGS
• Knowledge Gaps
• How injection and production interrelate to cause
  MEQ activity
• Stress distribution
• Geologic model
• Reservoir pressure and temperatures changes
• Geochemical responses related to MEQs and
  reservoir and fluid-matrix interaction
• Mitigation of deleterious chemical species (high
  gas, HCl)

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Future Objectives

• Close the Knowledge Gaps Well coordinated
  integrated collaborative projects involving
  Industry, National Laboratories, Universities,
  and the USGS
• Resource Expansion
• High resolution remote (surface) fracture and
  fluid mapping
• Couple mechanical properties, regional and local
  stress to stimulated fracture geometries and
  permeability
• MEQ activity, spatial distribution with respect
  to pre-existing fracture networks, improved
  hydraulic properties of the reservoir and
  differentiation between induced and natural
  seismicity
• Geometry, scale and surface area of fluid-rock
  exchange thermal and chemical
• Advanced modeling techniques for coupling
  geophysics, geochemistry, reservoir properties to
  maximize resource productivity and minimize
  societal impact.
• Exploration
• Reassessment of geothermal potential
• Improved understanding of geothermal systems
  Basin and Range
• Large Scale Numerical Simulation Test Facility
• Testable model of an enhanced/engineered
  geothermal system can one be devised that
  mimics a field site?

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Lawrence Berkeley National Laboratory

• Industry Collaboration
• Provide access to data and field sites for EGS
  research and development
• Strong commitment to the EGS concept
• Industry consortium to pool resources and
  information?