DOE Geothermal Research

• Geoscience and Related Technology

• Exploration and Drilling

• Energy Systems Research & Testing

Programmatic Objectives

• Decrease the cost of power

• Increase geothermal use - electrical and direct use

• Increase states with electrical generation

DOE Geoscience

• Research to reduce cost of electricity and expand geothermal use

– Improved exploration

– Better engineering

– Technology transfer/Industry collaboration

DOE Geoscience

• Resource Enhancement

• Exploration Technology Development

• Geothermal Resource Exploration and Definition (GRED)

 

Resource Enhancement

• Develop an adequate understanding of geothermal systems in order to find (in conjunction with the Exploration program element), enhance, and engineer geothermal systems

• Provide updated estimates of the geothermal resources available for development in the United States in conjunction with USGS

Resource Enhancement

• Improve the efficiency and sustainability of energy recovery from geothermal systems by engineering of natural and stimulated natural geothermal systems

• Carry out a cost-effective research and development program so that industry can make decisions about using EGS systems.

Exploration

 

• Develop and test innovative techniques for exploring for geothermal resources

 

• Reduce the cost of drilling through improved well-siting by applying new exploration and characterization techniques

Geothermal Resource Exploration and Definition (GRED)

Industry cost-shared exploration projects

To find, evaluate, and define additional geothermal resources throughout the western United States

Research Team

• National Laboratories - INEEL, LBNL, LLNL

• Universities

• Industry partners - EGS and GRED

Research topics

• Geochemistry

• Geology

• Exploration Models

• Geophysical Tools for Resource Characterization, Exploration and Monitoring

• Resource Analysis

• Reservoir Engineering

• Reservoir Characterization & Management

• Production and Injection Strategies

• Rock Mechanics

• Thermoelastic Hydraulic Fracture Design

• Tracers

Idaho National Engineering and Environmental Laboratory

INEEL Geoscience Activities

J.L. Renner

Idaho National Engineering and Environmental Laboratory

INEEL Geoscience

• Research supporting resource enhancement and exploration

• Objectives:

– Develop reservoir engineering tools

• Hydrothermal systems

• Engineered systems (EGS)

– Investigate improved exploration methods

Idaho National Engineering and Environmental Laboratory

EGS &Hydrothermal Characterization

• Objective: Develop methods to identify

permeability structure, anisotropy, and flow

volume for engineered and fluid-starved systems.

• Approach:

– Extend Tracer Test Analysis to fractured media

– Develop tracer selection criteria.

Idaho National Engineering and Environmental Laboratory

Existing Tracer Test Interpretation Problems (from Maxfield et al., 2003)

0

200

400

600

800

1000

1200

0 20 40 60 80 100Volume of Carrier gas at amb.

Con

cent

ratio

n

Experiment 1

Experiment 2

Experiment 3

Tracer is retarded (adsorbed) as moisture content of sandpack decreases. Cannot interpret tracer test results correctly if superheated conditions prevail. We need better tracer selection criteria.

Idaho National Engineering and Environmental Laboratory

Injection into Fluid-Starved Environments

Objective: Determine optimal use of injectate by studying relative influence of:

- Liquid saturation

- NCG concentration

- Power generation efficiency.

Approach: Extend work of Truesdell and Shook (1997), Stark (2001) by numerically simulating injection into HTR vs. NVDR in NW Geysers.

Idaho National Engineering and Environmental Laboratory

Example: Effect of Injection Location on NCG Production

Injection just above HTR

0

10

20

30

40

50

60

0 500 1000 1500

Time (Days)

Flo

wrate

0

0.005

0.01

0.015

0.02

0.025

0.03

NC

G W

t. F

r.

Injection within the HTR

0

10

20

30

40

50

60

0 500 1000 1500Time (Days)

Flo

wra

te

0

0.005

0.01

0.015

0.02

0.025

0.03

NC

G W

t. F

r.

Injection just above the HTR results in complete boiling of injectate without high concentrations of NCG.

Injection within the HTR doesn’t add to production rate, but does create a NCG bank. Higher NCG production reduces generation efficiency by 7%.

Idaho National Engineering and Environmental Laboratory

Improved Numerical Tools

Objective: Develop improved numerical tools.

Approach:

- New Wellbore flow correlation (SAIC)

- Inverse Model for Tetrad – Tet-1 (INEEL)

- Integrated Reservoir and Geophysics models –

TetGeo (collaborative project, RFP outstanding)

- TetGeo-1 in FY04.

Idaho National Engineering and Environmental Laboratory

Multi-phase Flow Correlation

• Developing new steam-water correlations for high, medium, and low enthalpy well data provided by Unocal, CalEnergy, SAIC.

• Available for ALL wellbore simulators in FY04.

Idaho National Engineering and Environmental Laboratory

Automatic History Matching (Inverse Modeling) – Tet-1

• Public Domain Inverse Model PEST Coupled to

Tetrad

– Tet-1 executes multiple commands; easy to

extend to (TETRAD + Geophysics) model

• Strong Industry Support (Caithness, CalEnergy,

Unocal, SAIC, Stanford U, etc.)

• Available for beta-test April 2003.

Idaho National Engineering and Environmental Laboratory

Coupled Reservoir Plus GeophysicsTetGeo and TetGeo-1

• Integrating models increases observations

– more data reduces uncertainty

• Field Management AND Exploration Tool

• Extend TetGeo to TetGeo-1 in FY04.

Idaho National Engineering and Environmental Laboratory

New Exploration Strategies in the B&R

• Aeromag surveys as an exploration tool

– Demonstrated utility in locating faults at DV

– Inexpensive, rapid means of regional analysis

– Combined with heat flow, geologic mapping

gives more precise description of resource.

Idaho National Engineering and Environmental Laboratory

Dixie Valley Aeromag and Mapped Faults

Faults inferred from Maximum Horizontal Gradient in gravity (shaded relief) correlate with mapped faults (yellow lines). From Smith, 2003.

Idaho National Engineering and Environmental Laboratory

Soda Lake

Occurs in Carson Sink where active resurfacing obscures surface evidence of faults

Recent (~10ka) volcanism

Potential dike and/or other basalt intrusion

Relationship of geothermal system to faults and intrusions is not known

High-resolution aeromag particularly useful because of active deposition and young volcanism.

Idaho National Engineering and Environmental Laboratory

Applying ‘Lessons Learned’ from Dixie Valley – B&R data constructs

Evaluating the importance of the DV studies:

– Synthesis of available spatially referenced data for known B&R systems

– Development of overlays (thematic layers) of geologic, geochemical, and geophysical data

– Analysis to discover most important exploration criteria, most important surveys to perform

– Selection of additional areas for future exploration.

Idaho National Engineering and Environmental Laboratory

Miscellaneous

• Prepare synthesis of Dixie Valley research

• Assist USGS with exploration data collection

• High temperature probe

• Support geoscience program

Idaho National Engineering and Environmental Laboratory

INEEL Accomplishments

• A suite of reservoir simulation methods

– To be used with existing simulators

– To better characterize geothermal fields

• Improved injection practices

• Cost effective exploration methods