Geothermal/Exploration

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Geothermal Exploration

Geothermal Exploration searches the earth’s subsurface for geothermal resources that can be extracted for the purpose of electricity generation. A geothermal resource is as commonly a volume of hot rock and water, but in the case of EGS, is simply hot rock. Geothermal exploration programs utilize a variety of techniques to identify geothermal reservoirs as well as information that can point to areas of low density, high porosity, high permeability, and subsurface fault lines that can help define well field development.

Groups of Exploration Techniques

There are many different techniques that are utilized in geothermal exploration depending on the region’s geology, economic considerations, project maturity, and other considerations such as land access and permitting requirements. Geothermal techniques can be broken into the following categories:

Full List of Exploration Techniques

Exploration Phases

Geothermal exploration is commonly separated into phases - a set of techniques that the developer will use to determine if a location is worth investigating further. Many geothermal developers define phases based on economic considerations and permitting requirements. Typically a developer will perform the least expensive techniques earlier on in the exploration program to reduce the risk of drilling a well with inadequate temperatures or flow. For example many developers will start with a desktop analysis, which includes a review of existing exploration techniques, a site visit, and in some cases inexpensive remote sensing techniques. If that set of techniques shows favorable conditions the developer will move on to the next phase. It is not uncommon for developers to start exploration at 5-10 locations and only drill at 1 location.

Note: The exploration phases described here should not be confused with the GEA Development Phases. The GEA Development Phases are used for reporting which stage in development a power plant is in (i.e. Procurement, Exploration, Permitting, Construction)^[1].

Typical Exploration Phases^[2]

Phase 1 - Regional Reconnaissance: for example: Geothermal Literature Review, Geothermometry, Multispectral Imaging, Data Acquisition-Manipulation

Phase 2 - Prospect Evaluation: for example: Hyperspectral Imaging, Compound and Elemental Analysis, Geothermometry, Field Mapping, Modeling-Computer Simulations

Phase 3 - Project Appraisal: for example: Geophysical Techniques, Field Mapping, Modeling-Computer Simulations

Phase 4 - Exploratory Drilling: for example: Thermal Gradient Holes, Core Holes, Slim Holes, Modeling-Computer Simulations

Exploration Best Practices

At a workshop in March 2013, IFC (International Finance Corporation), a member of the Word Bank Group, together with the International Geothermal Association launched “Geothermal Exploration Best Practices: A Guide to Resource Data Collection, Analysis, and Presentation for Geothermal Projects” in Istanbul, Turkey.

This Best Practice Guide for Geothermal Exploration was produced for IFC by GeothermEx, Inc. and outlines procedures and exploration techniques for geothermal projects and provides guidelines for presenting a geothermal project to funding entities and insurance companies. A focus is placed on high temperature geothermal resources for electricity generation. Project focus is also to attract potential investors by mitigating the associated risks with the help of insurance companies.

1st Edition (March 2013):

GeothermEx (International Finance Corporation (IFC)). 2013. Geothermal Exploration Best Practices: A Guide to Resource Data Collection, Analysis and Presentation for Geothermal Projects. Bochum, Germany: International Geothermal Association.

2nd Edition (June 2014):

Colin Harvey, Graeme Beardsmore, Inga Moeck, Horst Rüter, Stefan Bauer (International Geothermal Association). 2014. Best Practices Guide for Geothermal Exploration. 2nd Edition. Bochum, Germany: International Finance Corporation (IFC).

Exploration Cost and Time

The costs of exploration and the time required to complete an exploration program both add to the risk associated with the development of geothermal power plants. A typical geothermal exploration program for an individual location may require a financial commitment of 7 Million USD prior to drilling the first exploration hole^[2]. The time required to bring a geothermal power plant online in many cases is at least 3-5 years with the majority of that time due to exploration^[3]. In the case of Glass Mountain KGRA in Northern California the permitting delays were significant enough that it took over 20 years to complete an exploration program^[3].

A representation of the cost and time commitments required for a typical geothermal exploration program can be viewed and modified using the Exploration Cost and Time Metric tool that was developed from a collaboration between government and industry.

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Looking for exploration techniques that might provide Structural Information? Thermal Information? This query has been included to allow you to use the black arrows in the table header cells to sort the table data.

Technique	Exploration Group	Exploration Sub Group	Lithology Info Provided	Structure/Stratigraphic Info Provided	Hydrologic Info Provided	Thermal Info Provided
2-M Probe Survey	Field Techniques	Data Collection and Mapping				Identify and delineate shallow thermal anomalies
Acoustic Logs	Downhole Techniques	Well Log Techniques	determine porosity of layers	map discontinuities to determine their orientation.
Active Seismic Methods	Geophysical Techniques	Seismic Techniques
Active Seismic Techniques	Geophysical Techniques	Seismic Techniques	Rock unit density influences elastic wave velocities.	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Active Sensors	Remote Sensing Techniques	Active Sensors		Detect fault and ground movement, delineate faults, create high-resolution DEMS, quantify fault kinemaics, develop lineament maps, Geophysical Monitoring	Can give indications about subsurface geothermal fluid flow
Aerial Photography	Remote Sensing Techniques	Passive Sensors		map structures/faults	map surface water features	if photos taken in winter snow cover, can map thermal anomalies
Aeromagnetic Survey	Geophysical Techniques	Magnetic Techniques		map structure, basin fill thickness, and magnetic mineral concentrations in ore bodies
Airborne Electromagnetic Survey	Geophysical Techniques	Electrical Techniques	provide data on rock type and mineral content		can be used to detect changes in density of fluids and indicate if there is salt water intrusion
Airborne Gravity Survey	Geophysical Techniques	Gravity Techniques	Distribution of density in the subsurface enables inference of rock type.	Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity.	Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)	Determination of potential heat source of the system related to the low density signature of molten intrusions. (Bruhn, 2010)
Analytical Modeling	Data and Modeling Techniques	Modeling Techniques
Audio-Magnetotellurics	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Borehole Seismic Techniques	Downhole Techniques	Borehole Seismic Techniques	Rock unit density influences elastic wave velocities	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation	High temperatures and pressure impact the compressional and shear wave velocities
Caliper Log	Downhole Techniques	Well Log Techniques
Cation Geothermometers	Geochemical Techniques	Geochemical Data Analysis				Used to estimate reservoir temperatures.
Cement Bond Log	Downhole Techniques	Well Log Techniques
Chemical Logging	Downhole Techniques	Well Log Techniques			Presence and geochemical composition of fluid producing zones	Calcium-alkalinity ratios versus depth assist in defining warm and hot water aquifers
Compound and Elemental Analysis	Lab Analysis Techniques	Fluid Lab Analysis			Results can aid in the determination of fluid source regions and circulation pathways.	Certain elements exhibit high spatial correlation with high-temperature geothermal systems.
Conceptual Model	Data and Modeling Techniques	Modeling Techniques	Rock types, rock chemistry, stratigraphic layer organization	Location and shape of permeable and non-permeable structures, faults, fracture patterns	Hydrothermal fluid flow characteristics, up-flow patterns	Temperature and pressure extrapolation throughout reservoir, heat source characteristics
Controlled Source Audio MT	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Controlled Source Frequency-Domain Magnetics	Geophysical Techniques	Magnetic Techniques			Locate geothermal groundwater and flow patterns.
Core Analysis	Lab Analysis Techniques	Rock Lab Analysis	Core analysis is done to define lithology.	Core analysis can locate faults or fracture networks. Oriented core can give additional important information on anisotropy.		Thermal conductivity can be measured from core samples.
Core Holes	Drilling Techniques	Exploration Drilling	Core holes are drilled to identify lithology and mineralization	Retrieved samples can be used to identify fracture networks or faults		Thermal conductivity measurements can be done on retrieved samples.
Cross-Dipole Acoustic Log	Downhole Techniques	Well Log Techniques		Rock stress and fracture analysis	Use for fracture identification in open and cased holes. Also used for evaluating hydro fracturing/well stimulation effectiveness.
Cuttings Analysis	Lab Analysis Techniques	Rock Lab Analysis	Cuttings are used to define lithology
DC Resistivity Survey (Dipole-Dipole Array)	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
DC Resistivity Survey (Mise-A-La-Masse)	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
DC Resistivity Survey (Pole-Dipole Array)	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
DC Resistivity Survey (Schlumberger Array)	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
DC Resistivity Survey (Wenner Array)	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Data Acquisition-Manipulation	Data and Modeling Techniques	Data Techniques
Data Collection and Mapping	Field Techniques	Data Collection and Mapping	Map surface geology and hydrothermal alteration. Bulk and trace element analysis of rocks, minerals, and sediments. Identify and document surface geology and mineralogy. Rapid and unambiguous identification of unknown minerals.'"`UNIQ--ref-000034B3-QINU`"'Using "ReferenceForhttp://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html" as property chain is not permitted during the annotation process.	Locates active faults in the area of interest. Map fault and fracture patterns, kinematic information	Can reveal whether faults are circulating hydrothermal fluids. Map surface manifestations of geothermal systems.	Identify and delineate shallow thermal anomalies. Map surface temperature.
Data Techniques	Data and Modeling Techniques	Data Techniques
Data and Modeling Techniques	Data and Modeling Techniques		Rock types, rock chemistry, stratigraphic layer organization	Stress fields and magnitudes, location and shape of permeable and non-permeable structures, faults, and fracture patterns	Visualization and prediction of the flow patterns and characteristics of geothermal fluids, hydrothermal fluid flow characteristics, up-flow patterns	Thermal conduction and convection patterns in the subsurface, temperature and pressure extrapolation throughout reservoir, heat source characteristics
Density Log	Downhole Techniques	Well Log Techniques	provides data on the bulk density of the rock surrounding the well	Stratigraphic correlation between well bores.	Porosity of the formations loggesd can be calculated for the Density log andprovide an indication potential aquifers.
Development Drilling	Drilling Techniques	Development Drilling	Identify lithology and mineralization, provide core samples and rock cuttings	Retrieved samples can be used to identify stratigraphy and structural features such as fracture networks or faults	-Water samples can be used for geochemical analysis -Fluid pressures can be used to estimate flow rates	-Temperatures can be measured within the hole -Thermal conductivity measurements can be done on retrieved samples.
Direct-Current Resistivity Survey	Geophysical Techniques	Electrical Techniques	Rock type, mineral and clay content may be inferred.	Determination of fracture zones, faults, depth to groundwater aquifers.	Resistivity influenced by porosity, permeability, fluid saturation, fluid type and phase state of the pore water.	Resistivity influenced by temperature.'"`UNIQ--ref-00006FFB-QINU`"'
Downhole Fluid Sampling	Downhole Techniques	Well Testing Techniques			Water composition and source of fluids. Gas composition and source of fluids.	Water temperature. Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures.
Downhole Techniques	Downhole Techniques		Determination of lithology, grain size	Thickness and geometry of rock strata, fracture identification	Porosity, permeability, water saturation	Formation temperature with depth
Drilling Methods
Drilling Techniques	Drilling Techniques		Identify lithology and mineralization, provide core samples and rock cuttings	Retrieved samples can be used to identify stratigraphy and structural features such as fracture networks or faults	-Water samples can be used for geochemical analysis -Fluid pressures can be used to estimate flow rates	-Temperatures can be measured within the hole -Thermal conductivity measurements can be done on retrieved samples.
Earth Tidal Analysis	Downhole Techniques	Well Testing Techniques	Enables estimation of in-situ reservoir elastic parameters.		Enables estimation of in-situ reservoir hydraulic parameters.
Electrical Profiling Configurations	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Electrical Techniques	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Electromagnetic Profiling Techniques	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Electromagnetic Sounding Techniques	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Electromagnetic Techniques	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Exploration Drilling	Drilling Techniques	Exploration Drilling	Identify lithology and mineralization, provide core samples and rock cuttings	Retrieved samples can be used to identify stratigraphy and structural features such as fracture networks or faults	-Water samples can be used for geochemical analysis -Fluid pressures can be used to estimate flow rates	-Temperatures can be measured within the hole -Thermal conductivity measurements can be done on retrieved samples.
Exploratory Boreholes	Drilling Techniques	Exploration Drilling	Can provide core or cuttings	Identify stratigraphy and structural features within a borehole	-Water samples can be used for geochemical analysis<br:/>-Fluid pressures can be used to estimate flow rates	-Temperatures can be measured within the hole<br:/>-Information about the heat source
Exploratory Well	Drilling Techniques	Exploration Drilling	Can provide core or cuttings	Identify stratigraphy and structural features within a well	-Water samples can be used for geochemical analysis<br:/>-Fluid pressures can be used to estimate flow rates	-Temperatures can be measured within the hole<br:/>-Information about the heat source
FLIR	Remote Sensing Techniques	Passive Sensors				Map surface temperatures
Fault Mapping	Field Techniques	Data Collection and Mapping		Locates active faults in the area of interest	Can reveal whether faults are circulating hydrothermal fluids
Field Mapping	Field Techniques	Data Collection and Mapping	Map surface geology and hydrothermal alteration.	Map fault and fracture patterns, kinematic information.	Map surface manifestations of geothermal systems.	Map surface temperature.
Field Sampling	Field Techniques	Field Sampling	Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples.	Can reveal relatively high permeability zones. Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting.	Water composition and source of fluids. Isotope geochemistry can reveal fluid circulation of a geothermal system.	Water temperature. Used to locate active hydrothermal systems. Thermal conductivity of a rock sample can provide information to calculate heat flow. Hydrothermal alteration of a rock sample can indicate certain temperature or fluid compositions.
Field Techniques	Field Techniques		Map surface geology and hydrothermal alteration. Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples. Bulk and trace element analysis of rocks, minerals, and sediments. Identify and document surface geology and mineralogy. Rapid and unambiguous identification of unknown minerals.'"`UNIQ--ref-0000349B-QINU`"'Using "ReferenceForhttp://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html" as property chain is not permitted during the annotation process.	Locates active faults in the area of interest. Map fault and fracture patterns, kinematic information. Can reveal relatively high permeability zones. Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting.	Can reveal whether faults are circulating hydrothermal fluids. Map surface manifestations of geothermal systems. Water composition and source of fluids. Isotope geochemistry can reveal fluid circulation of a geothermal system.	Identify and delineate shallow thermal anomalies. Map surface temperature. Water temperature. Used to locate active hydrothermal systems. Thermal conductivity of a rock sample can provide information to calculate heat flow. Hydrothermal alteration of a rock sample can indicate certain temperature or fluid compositions.
Flow Test	Downhole Techniques	Well Testing Techniques			Flow tests provide information on permeability, recharge rates, reservoir pressures, fluid chemistry, and scaling.	Flow tests can measure temperature variations with time to estimate characteristics about the heat source.
Fluid Inclusion Analysis	Lab Analysis Techniques	Fluid Lab Analysis			Fluid composition at a point in time and space	The minimum temperature of fluid inclusion formation
Fluid Lab Analysis	Lab Analysis Techniques	Fluid Lab Analysis			Results can aid in the determination of fluid source regions and circulation pathways, and assist in determining the degree of mixing between different hydrothermal fluids.	Certain elements exhibit high spatial correlation with high-temperature geothermal systems; Isotopic ratios can be used to characterize and locate subsurface thermal anomalies.
Formation Testing Techniques	Downhole Techniques	Formation Testing Techniques
Frequency-Domain Electromagnetic Survey	Geophysical Techniques	Electrical Techniques	Detection of high-conductivity bodies in the subsurface.			Detection of the presence of a thermal anomaly through its resistivity signature.
Gamma Log	Downhole Techniques	Well Log Techniques	provides information on changes in rock type near the wellbore from changes in measured gamma radiation	using multiple gamma logs over an area, the depth to the sandstone and shale layers can be correlated over larger areas
Gas Flux Sampling	Field Techniques	Field Sampling		High flux can be indicative of conduits for fluid flow.		Anomalous flux is associated with active hydrothermal activity.
Gas Geothermometry	Geochemical Techniques	Geochemical Data Analysis
Gas Sampling	Field Techniques	Field Sampling		High flux can be indicative of conduits for fluid flow.	Gas composition and source of fluids.	Anomalous flux is associated with active hydrothermal activity. Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures.
GeoTeam
Geochemical Data Analysis	Geochemical Techniques	Geochemical Data Analysis
Geochemical Techniques	Geochemical Techniques
Geodetic Survey	Remote Sensing Techniques	Passive Sensors		Map regional strain rates
Geographic Information System	Data and Modeling Techniques	Data Techniques	Any mapable information	Any mapable information	Any mapable information	Any mapable information
Geophysical Methods	Geophysical Techniques	Geophysical Techniques
Geophysical Techniques	Geophysical Techniques		may be inferred	may be inferred	may be inferred	may be inferred
Geothermal Literature Review	Data and Modeling Techniques	Data Techniques
Geothermometry	Geochemical Techniques	Geochemical Data Analysis				used to estimate reservoir temperatures
Gravity Methods	Geophysical Techniques	Gravity Techniques
Gravity Techniques	Geophysical Techniques	Gravity Techniques	Distribution of density in the subsurface enables inference of rock type.	Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity.	Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)	Determination of potential heat source of the system related to the low density signature of molten intrusions. (Bruhn, 2010)
Ground Electromagnetic Techniques	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Ground Gravity Survey	Geophysical Techniques	Gravity Techniques	Distribution of density in the subsurface enables inference of rock type.	Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and large-scale deposition of silicates due to hydrothermal activity.	Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)	Determination of potential heat source of the system related to the low density signature of molten intrusions. (Bruhn, 2010)
Ground Magnetics	Geophysical Techniques	Magnetic Techniques	Presence of magnetic minerals such as magnetite.	Mapping of basement structures, horst blocks, fault systems, fracture zones, dykes and intrusions.	The circulation of hydrothermal fluid may impact the magnetic susceptibility of rocks.	Rocks lose their magnetic properties at the Curie temperature (580° C for magnetite) '"`UNIQ--ref-00010B24-QINU`"' and, upon cooling, remagnetize in the present magnetic field orientation. The Curie point depth in the subsurface may be determined in a magnetic survey to provide information about hydrothermal activity in a region.
Groundwater Sampling	Field Techniques	Field Sampling			Water composition and source of fluids. Determination of mixing ratios between different fluid end-members. Determination of fluid recharge rates and residence times.	Water temperature.
Hand-held X-Ray Fluorescence (XRF)	Field Techniques	Data Collection and Mapping	Bulk and trace element analysis of rocks, minerals, and sediments.
Hydroprobe	Drilling Techniques	Exploration Drilling			Collection of ground water samples for geochemistry and geothermometry	Temperature measurements down to 50 m
Hyperspectral Imaging	Remote Sensing Techniques	Passive Sensors	mineral maps can be used to show the presence of hydrothermal minerals and mineral assemblages	aerial photographs can show structures	delineate locations of surface water features	vegetation maps can show plants stressed due to nearby thermal activity
Image Logs	Downhole Techniques	Well Log Techniques	Identify different lithological layers, rock composition, grain size, mineral, and clay content	-Fault and fracture identification -Rock texture, porosity, and stress analysis -determine dip, thickness, and geometry of rock strata in vicinity of borehole -Detection of permeable pathways, fracture zones, faults	Locate zones of aquifer inflow/outflow
InSAR	Remote Sensing Techniques	Active Sensors		Geophysical Monitoring	Can give indications about subsurface geothermal fluid flow
Injectivity Test	Downhole Techniques	Well Testing Techniques			Permeability of the well
Isotope Geothermometry	Geochemical Techniques	Geochemical Data Analysis
Isotopic Analysis- Fluid	Lab Analysis Techniques	Fluid Lab Analysis	Water rock interaction		Origin of hydrothermal fluids; Mixing of hydrothermal fluids	Isotopic ratios can be used to characterize and locate subsurface thermal anomalies.
Isotopic Analysis- Rock	Lab Analysis Techniques	Rock Lab Analysis	Water rock interaction
Lab Analysis Techniques	Lab Analysis Techniques		Water rock interaction; Rapid and unambiguous identification of unknown minerals; Bulk and trace element analysis of rocks, minerals, and sediments; Obtain detailed information about rock composition and morphology; Determine detailed information about rock composition and morphology; Cuttings are used to define lithology; Core analysis is done to define lithology	Anomalously high concentrations can indicate high permeability or conduit for fluid flow; Identify historic structure and deformation of land; Core analysis can locate faults or fracture networks. Oriented core can give additional important information on anisotropy	Reconstructing the fluid circulation of a hydrothermal system; Field wide soil sampling can generate a geometrical approximation of fluid circulation; Determine origin of hydrothermal fluids; Calculate mixing ratios of hydrothermal fluids; Determine fluid composition at a point in time and space	High mercury vapor concentration in soils can be indicative of active hydrothermal activity; Isotopic ratios can be used to characterize and locate subsurface thermal anomalies; Constrain the minimum temperature of fluid inclusion formation; certain elements exhibit high spatial correlation with high-temperature geothermal systems; Thermal conductivity can be measured from core samples
LiDAR	Remote Sensing Techniques	Active Sensors		delineate faults, create high-resolution DEMS, quantify fault kinemaics, develop lineament maps
Liquid Geothermometry	Geochemical Techniques	Geochemical Data Analysis
Long-Wave Infrared	Remote Sensing Techniques	Passive Sensors	Map characteristic minerals associated with hot springs/mineral deposits			Map surface temperatures
Macrophotography	Field Techniques	Data Collection and Mapping	Identify and document surface geology and mineralogy
Magnetic Techniques	Geophysical Techniques	Magnetic Techniques	Presence of magnetic minerals such as magnetite.	Mapping of basement structures, horst blocks, fault systems, fracture zones, dykes and intrusions.	The circulation of hydrothermal fluid may impact the magnetic susceptibility of rocks.	Rocks lose their magnetic properties at the Curie temperature (580° C for magnetite) '"`UNIQ--ref-0001EF84-QINU`"' and, upon cooling, remagnetize in the present magnetic field orientation. The Curie point depth in the subsurface may be determined in a magnetic survey to provide information about hydrothermal activity in a region.
Magnetotelluric Techniques	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Magnetotellurics	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Mercury Vapor	Lab Analysis Techniques	Fluid Lab Analysis		Anomalously high concentrations can indicate high permeability or conduit for fluid flow	Field wide soil sampling can generate a geometrical approximation of fluid circulation	High concentration in soils can be indicative of active hydrothermal activity
Micro-Earthquake	Geophysical Techniques	Seismic Techniques		Fault zones, permeable pathways	Fluid type- liquid or steam
Microgravity-Hybrid Microgravity	Geophysical Techniques	Gravity Techniques		Ground subsidence can be mapped using microgravity	Monitoring net mass changes of a geothermal reservoir due to production and reinjection processes	Changes in liquid density due to temperature changes in the reservoir
Microhole Array	Drilling Techniques	Exploration Drilling			May be possible to assess fluid flow using small-diameter downhole tools designed for slim holes.	May be possible to collect limited temperature data using small-diameter downhole tools designed for slim holes.
Modeling Techniques	Data and Modeling Techniques	Modeling Techniques	Rock types, rock chemistry, stratigraphic layer organization	Stress fields and magnitudes, location and shape of permeable and non-permeable structures, faults, fracture patterns	Visualization and prediction of the flow patterns and characteristics of geothermal fluids, hydrothermal fluid flow characteristics, up-flow patterns	Thermal conduction and convection patterns in the subsurface, temperature and pressure extrapolation throughout reservoir, heat source characteristics
Modeling-Computer Simulations	Data and Modeling Techniques	Modeling Techniques		Stress fields and magnitudes	Visualization and prediction of the flow patterns and characteristics of geothermal fluids	Thermal conduction and convection patterns in the subsurface
Mud Logging	Downhole Techniques	Well Log Techniques	Lithological layers are identified from drill cuttings	Porosity of rocks	Fluid content of the borehole while drilling can be determined
Multicomponent Geothermometers	Geochemical Techniques	Geochemical Data Analysis
Multispectral Imaging	Remote Sensing Techniques	Passive Sensors	relative mineral maps	aerial photographs can show structures	delineate locations of surface water features	vegetation maps can show plants stressed due to nearby thermal activity
Near Infrared Surveys	Remote Sensing Techniques	Passive Sensors
Neutron Log	Downhole Techniques	Well Log Techniques	if used in conjunction with other logs, this technique can provide information on the rock type and the porosity	Corelation of rock units	Estimate of formation porosity
Numerical Modeling	Data and Modeling Techniques	Modeling Techniques		Stress fields and magnitudes	Visualization and prediction of the flow patterns and characteristics of geothermal fluids	Thermal conduction and convection patterns in the subsurface
Oblique Aerial & Ground Visible Band & Thermographic Imaging	Remote Sensing Techniques	Passive Sensors
Observation Wells	Drilling Techniques	Development Drilling			Total dissolved solids, fluid pressure, flow rates, and flow direction	Monitors temperature of circulating fluids
Over Core Stress	Lab Analysis Techniques	Rock Lab Analysis
PSInSAR	Remote Sensing Techniques	Active Sensors		Detect fault and ground movement	Can give indications about subsurface geothermal fluid flow
Paleomagnetic Measurements	Lab Analysis Techniques	Rock Lab Analysis	Can determine detailed information about rock composition and morphology	Historic structure and deformation of land
Passive Seismic Techniques	Geophysical Techniques	Seismic Techniques	Rock unit density influences elastic wave velocities.	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Passive Sensors	Remote Sensing Techniques	Passive Sensors	Mineral maps can be used to show the presence of hydrothermal minerals and mineral assemblages	Map structures/faults and regional strain rates	Map surface water features	Map surface temperatures
Petrography Analysis	Lab Analysis Techniques	Rock Lab Analysis	Provides detailed information about rock composition and morphology
Portable X-Ray Diffraction (XRD)	Field Techniques	Data Collection and Mapping	Rapid and unambiguous identification of unknown minerals.'"`UNIQ--ref-00008534-QINU`"'Using "ReferenceForhttp://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html" as property chain is not permitted during the annotation process.
Portfolio Risk Modeling	Data and Modeling Techniques	Modeling Techniques
Pressure Temperature Log	Downhole Techniques	Well Log Techniques		Perturbations in temperature or pressure can be indicative of faults or other structural features	fluid cirulation, over-pressured zones, and under-pressured zones.	Temperature profile with depth
Production Wells	Drilling Techniques	Development Drilling	Drill cuttings are analyzed to determine lithology and mineralogy	Fractures, faults, and geologic formations that the well passes through are identified and mapped.	Identify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistry	Direct temperature measurements from within the reservoir
Radar	Remote Sensing Techniques	Active Sensors		Detect fault and ground movement	Can give indications about subsurface geothermal fluid flow
Radiometrics	Remote Sensing Techniques	Passive Sensors	Primary use is in mapping potassium alterations
Reflection Survey	Geophysical Techniques	Seismic Techniques	Rock unit density influences elastic wave velocities.	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Refraction Survey	Geophysical Techniques	Seismic Techniques	Rock unit density influences elastic wave velocities.	Can provide information on crustal thickness, depth to basement.
Remote Sensing Techniques	Remote Sensing Techniques
Rock Density	Lab Analysis Techniques	Rock Lab Analysis	Density of different lithologic units.
Rock Lab Analysis	Lab Analysis Techniques	Rock Lab Analysis	Core and cuttings analysis is done to define lithology. Water rock interaction. Can determine detailed information about rock composition and morphology. Density of different lithologic units. Rapid and unambiguous identification of unknown minerals.'"`UNIQ--ref-00013FBB-QINU`"'Using "ReferenceForhttp://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html" as property chain is not permitted during the annotation process.	Core analysis can locate faults or fracture networks. Oriented core can give additional important information on anisotropy. Historic structure and deformation of land.		Thermal conductivity can be measured from core samples.
Rock Sampling	Field Techniques	Field Sampling	Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples.	Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting.	Isotope geochemistry can reveal fluid circulation of a geothermal system.	Thermal conductivity of a rock sample can provide information to calculate heat flow. Hydrothermal alteration of a rock sample can indicate certain temperature or fluid compositions.
SAR	Remote Sensing Techniques	Active Sensors		create high-resolution DEMs, detect fault and ground movement
SRT	Remote Sensing Techniques	Active Sensors		high-resolution DEMs
SWIR	Remote Sensing Techniques	Passive Sensors	map characteristic minerals associated with hot springs/mineral deposits
Seismic Techniques	Geophysical Techniques	Seismic Techniques	Rock unit density influences elastic wave velocities.	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Self Potential	Geophysical Techniques	Electrical Techniques	SP technique originally applied to locating sulfide ore-bodies.	Detection and tracing of faults.	Determination of fluid flow patterns: electrochemical coupling processes due to variations in ionic concentrations, and electrokinetic coupling processes due to fluid flow in the subsurface.	Location of near-surface thermal anomalies: thermoelectric coupling processes due to variations in temperature in the subsurface.
Silica Geothermometers	Geochemical Techniques	Geochemical Data Analysis				Used to estimate reservoir temperatures.
Single-Well And Cross-Well Seismic Imaging	Downhole Techniques	Borehole Seismic Techniques	Rock unit density influences elastic wave velocities.	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Single-Well and Cross-Well Resistivity	Downhole Techniques	Well Log Techniques	Identify different lithological layers, rock composition, mineral, and clay content	-Fault and fracture identification -Rock texture, porosity, and stress analysis -determine dip and structural features in vicinity of borehole -Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Slim Holes	Drilling Techniques	Exploration Drilling	If core is collected	If core is collected	Fluid flow and water chemistry	Thermal gradient or bottom hole temperature
Soil Gas Sampling	Field Techniques	Field Sampling		Identify concealed faults that act as conduits for hydrothermal fluids.	Identify hydrothermal gases of magmatic origin.	Differentiate between amagmatic or magmatic sources heat.
Soil Sampling	Field Techniques	Field Sampling		Can reveal relatively high permeability zones		Used to locate active hydrothermal systems
Spontaneous Potential Well Log	Downhole Techniques	Well Log Techniques	SP technique originally applied to locating sulfide ore-bodies.	-Formation bed thickness and boundaries -Detection and tracing of faults -Permeability and porosity	Determination of fluid flow patterns: electrochemical coupling processes due to variations in ionic concentrations, and electrokinetic coupling processes due to fluid flow in the subsurface.	Location of thermal anomalies: thermoelectric coupling processes due to variations in temperature in the subsurface.
SqueeSAR	Remote Sensing Techniques	Active Sensors		Detect fault and ground movement	Can give indications about subsurface geothermal fluid flow
Static Temperature Survey	Downhole Techniques	Well Testing Techniques				Extrapolate the true temperature of the formation the well penetrates
Step-out Well	Drilling Techniques	Exploration Drilling	Drill cuttings are analyzed to determine lithology and mineralogy	Fractures, faults, and geologic formations that the well passes through are identified and mapped	Identify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistry	Direct temperature measurements from within the reservoir
Stereo Satellite Imagery	Remote Sensing Techniques	Passive Sensors		map structures/faults	map surface water features, determine the boundary conditions of hydrothermal circulation
Stress Test	Downhole Techniques	Well Testing Techniques		Fracture distribution and ambient tectonic stresses	Fluid flow direction
Surface Gas Sampling	Field Techniques	Field Sampling			Gas composition and source of fluids.	Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures.
Surface Water Sampling	Field Techniques	Field Sampling			Water composition and source of fluids	Water temperature
Teleseismic-Seismic Monitoring	Geophysical Techniques	Seismic Techniques	Rock unit density influences elastic wave velocities.	Map geothermal reservoir geometry. Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Telluric Survey	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Thermal Gradient Holes	Drilling Techniques	Exploration Drilling			Field wide fluid flow characteristics if an array of wells are drilled	Mapping and projecting thermal anomalies
Thermal Ion Dispersion	Geochemical Techniques	Geochemical Data Analysis
Thermochronometry	Geochemical Techniques	Geochemical Data Analysis				Thermal history of area, rate of cooling, age that minerals reached closure temperature
Time-Domain Electromagnetics	Geophysical Techniques	Electrical Techniques	Detection of rock units or geological features with contrasting apparent resistivity.	Structural information may be inferred from TDEM data.	Hydrological information such as depth to groundwater table may be determined.	Extent of hydrothermal alteration mineralogy may be inferred.
Trace Element Analysis	Lab Analysis Techniques	Fluid Lab Analysis			Reconstructing the fluid circulation of a hydrothermal system
Tracer Testing	Downhole Techniques	Well Testing Techniques		Fracture zones and formation permeability	Flow rates, flow direction, hydrologic connections, storativity
Vertical Electrical Sounding Configurations	Geophysical Techniques	Electrical Techniques	Rock composition, mineral and clay content	Detection of permeable pathways, fracture zones, faults	Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water	Resistivity influenced by temperature
Vertical Flowmeter Test	Downhole Techniques	Well Testing Techniques			Define permeable zones within a well
Vertical Seismic Profiling	Downhole Techniques	Borehole Seismic Techniques	Rock unit density influences elastic wave velocities.	Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.	Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.	High temperatures and pressure impact the compressional and shear wave velocities.
Water Sampling	Field Techniques	Field Sampling			Water composition and source of fluids	Water temperature
Well Deepening	Drilling Techniques	Development Drilling	Drill cuttings are analyzed to determine lithology and mineralogy	Fractures, faults, and geologic formations that the well passes through are identified and mapped.	Identify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistry	Direct temperature measurements from within the reservoir
Well Log Techniques	Downhole Techniques	Well Log Techniques	depth and thickness of formations; lithology and porosity can be inferred	reservoir thickness, reservoir geometry, borehole geometry	permeability and fluid composition can be inferred	direct temperature measurements; thermal conductivity and heat capacity
Well Testing Techniques	Downhole Techniques	Well Testing Techniques	Enable estimation of in-situ reservoir elastic parameters	Fracture distribution, formation permeability, and ambient tectonic stresses	provides information on permeability, location of permeable zones recharge rates, flow rates, fluid flow direction, hydrologic connections, storativity, reservoir pressures, fluid chemistry, and scaling.	Temperature variations with time Extrapolate the true temperature of formation
X-Ray Diffraction (XRD)	Lab Analysis Techniques	Rock Lab Analysis	Rapid and unambiguous identification of unknown minerals.'"`UNIQ--ref-00008470-QINU`"'Using "ReferenceForhttp://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html" as property chain is not permitted during the annotation process.
X-Ray Fluorescence (XRF)	Lab Analysis Techniques	Rock Lab Analysis	Bulk and trace element analysis of rocks, minerals, and sediments.
Z-Axis Tipper Electromagnetics	Geophysical Techniques	Electrical Techniques

[edit]

Geothermal Regulations and Permitting for Exploration

For information about regulations and permitting related to exploration for geothermal projects, see the Regulatory and Permitting Information Desktop Toolkit.

[edit]

Document #	Analysis Type	Applicant	Lead Agency	District Office	Field Office	Mineral Manager	Surface Manager	Techniques
DNA-NV-030-09-03	DNA	Dusty Miller LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOE-EA-1759	EA	Naknek Electric Association	United States Department of Energy	Golden Field Office	Golden Field Office	Naknek Electric Association	Naknek Electric Association
DOI-BLM-CA-170-02-15	EA	Mammoth Pacific	Bureau of Land Management	BLM Central California District Office	BLM Bishop Field Office	Bureau of Land Management		Exploration Drilling Slim Holes Exploratory Well Drilling Methods
DOI-BLM-CA-650-2005-086	EA	Robert A. Phinney, Deep Rose LLC	Bureau of Land Management	BLM California Desert District Office		Bureau of Land Management	Bureau of Land Management	Flow Test Exploratory Well
DOI-BLM-CA-670-2010-CX	CX	Ram Power	BLM California State Office	BLM California Desert District Office		Bureau of Land Management		Seismic Techniques
DOI-BLM-ID-110-2009-3825-CE	CX	Agua Caliente LLC	Bureau of Land Management	BLM Boise District Office	BLM Four Rivers Field Office		Bureau of Land Management
DOI-BLM-ID-220-2009-EA-3709	EA	Agua Caliente, LLC	Bureau of Land Management	BLM Twin Falls District Office	Burley Field Office	Bureau of Land Management	Bureau of Land Management	Exploration Drilling
DOI-BLM-ID-B010-2010-0083-CX	CX	Agua Caliente	BLM Idaho State Office	BLM Boise District Office	BLM Four Rivers Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-ID-B010-2010-??-CX	CX	Agua Caliente LLC	Bureau of Land Management	BLM Boise District Office	BLM Four Rivers Field Office		Bureau of Land Management
DOI-BLM-ID-I020-2012-0017-CX	CX	Idaho Geological Survey	Bureau of Land Management	BLM Idaho Falls District Office	BLM Pocatello Field Office	Bureau of Land Management	Bureau of Land Management
DOI-BLM-ID-T020-2012-0003-CX	CX	Agua Caliente LLC	BLM Idaho State Office	BLM Twin Falls District Office	BLM Burley Field Office	Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NM-L000-2012-0020-DNA	DNA	Lightning Dock Geothermal Inc	Bureau of Land Management	BLM Las Cruces District Office		Bureau of Land Management
DOI-BLM-NM-L000-2012-0042-DNA	DNA	Lightning Dock Geothermal Inc	Bureau of Land Management	BLM Las Cruces District Office		Bureau of Land Management
DOI-BLM-NM-L000-2012-0046-CX	CX	Lightning Dock Geothermal Inc	Bureau of Land Management	BLM Las Cruces District Office		Bureau of Land Management
DOI-BLM-NM-L000-2012-0111-DNA	DNA	Lightning Dock Geothermal Inc	Bureau of Land Management	BLM Las Cruces District Office		Bureau of Land Management		Drilling Techniques
DOI-BLM-NM-L000-2012-0218-DNA	DNA	Lightning Dock Geothermal Inc	Bureau of Land Management	BLM Las Cruces District Office		Bureau of Land Management		Well Testing Techniques
DOI-BLM-NV-0063-EA06-100	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Well Testing Techniques Drilling Techniques
DOI-BLM-NV-030-06-025-EA	EA		Bureau of Land Management	BLM Carson City District Office
DOI-BLM-NV-B020-2008-0071-DNA	DNA	Sierra Geothermal Partners	Bureau of Land Management	BLM Battle Mountain District Office
DOI-BLM-NV-B020-2008-????-??		Sierra Geothermal Power	Bureau of Land Management	BLM Battle Mountain District Office				Thermal Gradient Holes Seismic Techniques
DOI-BLM-NV-B020-2008-????-CX	CX	Sierra Geothermal Power	Bureau of Land Management	BLM Battle Mountain District Office
DOI-BLM-NV-B020-2009-0030-CX	CX	Sierra Geothermal Power	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management
DOI-BLM-NV-B020-2010-0106-CX	CX	Sierra Geothermal Power	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Magnetotellurics Z-Axis Tipper Electromagnetics Slim Holes Hyperspectral Imaging Magnetic Techniques
DOI-BLM-NV-B020-2010-????-CX	CX	Ormat Technologies Inc	BLM Nevada State Office	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-NV-B020-2011-0017-CX	CX	CHB Metal Foote Corporation	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management
DOI-BLM-NV-B020-2011-0026-EA	EA	Ram Power	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Well Testing Techniques Drilling Techniques Exploration Drilling
DOI-BLM-NV-B020-2011-0048-CX	CX	CHB Metal Foote Corporation	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management
DOI-BLM-NV-B020-2012-0214-EA	EA	Rockwood Lithium Inc	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Well Testing Techniques Drilling Techniques
DOI-BLM-NV-B020-????-???-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Battle Mountain District Office
DOI-BLM-NV-C010-2009-0006-EA	EA	Gradient Resources	BLM Stillwater Field Office	BLM Carson City District Office	BLM Stillwater Field Office	BLM Stillwater Field Office	BLM Stillwater Field Office	Thermal Gradient Holes
DOI-BLM-NV-C010-2009-0030-CX	CX	Vulcan Power Company	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-NV-C010-2009-0051-CX	CX	Global Magma Energy Group	BLM Nevada State Office	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Reclamation	Magnetotelluric Techniques
DOI-BLM-NV-C010-2010-0006-DNA	DNA	Ormat Technologies Inc	BLM Nevada State Office	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes Drilling Techniques
DOI-BLM-NV-C010-2010-0006-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Downhole Techniques Well Testing Techniques Drilling Techniques Exploration Drilling
DOI-BLM-NV-C010-2010-0008-CX	CX	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-C010-2010-0008-EA	EA	Magma Energy	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Downhole Techniques Well Testing Techniques Drilling Techniques Exploration Drilling
DOI-BLM-NV-C010-2010-0010-EA	EA	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Downhole Techniques Well Testing Techniques Drilling Techniques Exploration Drilling
DOI-BLM-NV-C010-2010-0052-CX	CX	Magma Energy	BLM Nevada State Office	BLM Carson City District Office	BLM Stillwater Field Office			Thermal Gradient Holes Drilling Techniques
DOI-BLM-NV-C010-2011-0004-CX	CX	AltaRock Energy Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office		Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-C010-2011-0014-CX	CX	Gradient Resources	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office		Bureau of Reclamation	Reflection Survey
DOI-BLM-NV-C010-2011-0015-CX	CX	Gradient Resources	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office		Bureau of Reclamation
DOI-BLM-NV-C010-2011-0019-CX	CX	Geoglobal US Gabbs LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office		Bureau of Land Management
DOI-BLM-NV-C010-2011-0504-CX	CX	Gradient Resources	Bureau of Land Management	BLM Carson City District Office BLM Winnemucca District Office			Bureau of Reclamation
DOI-BLM-NV-C010-2011-0516-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes Drilling Techniques
DOI-BLM-NV-C010-2011-0517-DNA	DNA	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Drilling Techniques
DOI-BLM-NV-C010-2011-0527-CX	CX	AltaRock Energy Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Passive Seismic Techniques
DOI-BLM-NV-C010-2012-0051-EA	EA	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Exploratory Well
DOI-BLM-NV-C010-2012-0057-CX	CX	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-NV-C010-2012-0069-CX	CX	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-NV-C010-2012-0070-CX	CX	US Navy Geothermal Program Office	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotelluric Techniques
DOI-BLM-NV-C010-2013-0022-DNA	DNA	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-NV-C010-????-????-CX	CX	Ormat Technologies Inc	Bureau of Land Management	BLM Carson City District Office				Thermal Gradient Holes
DOI-BLM-NV-CO1000-2010-0009-CX	CX	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Electromagnetic Techniques
DOI-BLM-NV-CO1000-2010-0010-CX	CX	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-CO1000-2010-0011-CX	CX	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Electromagnetic Techniques
DOI-BLM-NV-CO1000-2010-0021-CX	CX	TGP Dixie Development LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	BLM Nevada State Office	Magnetotelluric Techniques
DOI-BLM-NV-CO1000-2010-0022-CX	CX	Terra-Gen Power LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Seismic Techniques Magnetotelluric Techniques Electromagnetic Techniques
DOI-BLM-NV-E030-2011-0017-CX	CX	USGS	BLM Nevada State Office	BLM Elko District Office			Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-NV-E030-20??-????-??	EA	Standard Steam Trust LLC	BLM Nevada State Office	BLM Elko District Office
DOI-BLM-NV-W010-2009-0018-CX	CX	Gradient Resources	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management
DOI-BLM-NV-W010-2010-0004-EA	EA	Terra-Gen Power LLC	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Well Testing Techniques Exploration Drilling
DOI-BLM-NV-W010-2010-0039-CX	CX	Terra-Gen Power LLC	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Micro-Earthquake
DOI-BLM-NV-W010-2010-0040-CX	CX	Presco Energy LLC	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management Bureau of Reclamation	Bureau of Land Management Bureau of Reclamation	Reflection Survey
DOI-BLM-NV-W010-2010-0041-CX	CX	Stephen D. Muir	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-W010-2010-0043-CX	CX	Oski Energy LLC	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-W010-2010-0043-CX-2	CX	Geothermal Technical Partners	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes Well Testing Techniques Geophysical Techniques Slim Holes
DOI-BLM-NV-W010-2011-0001-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Well Testing Techniques Exploration Drilling Development Drilling
DOI-BLM-NV-W010-2011-0004-CX	CX	AltaRock Energy Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Passive Seismic Techniques
DOI-BLM-NV-W010-2011-0100-CX	CX	Ormat Nevada Inc.	BLM Nevada State Office	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management
DOI-BLM-NV-W030-2010-0006-EA	EA	US Geothermal Inc	United States Department of Energy	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management	Flow Test
DOI-BLM-NV-W030-2010-0021-CX	CX	US Geothermal Inc	Bureau of Land Management	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-W030-2011-0007-CX	CX	US Geothermal Inc	Bureau of Land Management	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management	Seismic Techniques
DOI-BLM-NV-W030-2012-0020-CX	CX	Nevada Bureau of Mines and Geology	Bureau of Land Management	BLM Winnemucca District Office				Thermal Gradient Holes
DOI-BLM-NV-W030-20??-????-CX	CX	Geothermal Technical Partners	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Gravity Techniques
DOI-BLM-NV-WO10-2014-0002-CX	CX	Ormat Technologies Inc	BLM Humboldt River Field Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	BLM Nevada State Office	BLM Nevada State Office	Thermal Gradient Holes
DOI-BLM-OR-P000-2010-0003-EA	EA	Davenport Power LLC	Bureau of Land Management	BLM Prineville District Office		Bureau of Land Management	United States Forest Service	Well Testing Techniques Drilling Techniques Exploration Drilling Seismic Techniques Passive Seismic Techniques
DOI-BLM-OR-P000-2012-0043-CX	CX	Ormat Technologies Inc	BLM Oregon State Office	BLM Prineville District Office			United States Forest Service	Thermal Gradient Holes
DOI-BLM-OR-P000-????-????-EA	EA	Davenport Power LLC	Bureau of Land Management	BLM Prineville District Office			United States Forest Service
DOI-BLM-OR-P040-0021-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Prineville District Office BLM Burns District Office		Bureau of Land Management	Bureau of Land Management	Drilling Techniques
DOI-BLM-OR-V040-2009-0059-CX	CX	US Geothermal Inc	Bureau of Land Management	BLM Vale District Office
DOI-BLM-UT-C010-????-????-CX	CX	ENEL Green Power North America	Bureau of Land Management	BLM Color Country District Office			United States Forest Service Bureau of Land Management
DOI-BLM-UT-W019-2011-0006-CX	CX	Utah Geological Survey	BLM Utah State Office	BLM West Desert District Office				Thermal Gradient Holes
DOI-BLM-UT-W019-2011-0007-CX	CX	Utah Geological Survey	BLM Utah State Office			Bureau of Land Management		Thermal Gradient Holes
DOI-BLM-UT-W020-2009-0028-EA	EA	Standard Steam Trust LLC	Bureau of Land Management	BLM West Desert District Office		Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-UT-W020-2010-0042-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM West Desert District Office		Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
DOI-BLM-UT-W020-2010-042-EA	EA	Ormat Technologies Inc	Bureau of Land Management	BLM West Desert District Office		Bureau of Land Management	Bureau of Land Management	Exploration Drilling Development Drilling
DOI-LM-NV-W010-2012-0061-CX	CX	Nevada Bureau of Mines and Geology	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
EA for Well Field Development at Patua Geothermal Area - DOI-BLM-NV-C010-2011-00016-EA	EA	Gradient Resources	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management Bureau of Reclamation	Thermal Gradient Holes Drilling Techniques Exploratory Well
EA-NV-030-05-08	EA	Nevada Geothermal Specialists, LLC	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	BLM Nevada State Office
GFO-04-236b, GFO-10-367		Chena Hot Springs Resort	Golden Field Office					Slim Holes
LLNV-WO1000-2009-0002-EA	EA	Ormat Technologies Inc	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Drilling Techniques Observation Wells
LLNV-WO1000-2009-0034-CX	CX	TGP Dixie Development Company, LLC	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	2-M Probe Survey Ground Magnetics
NEPA Process for Geothermal Power Plants in the Deschutes National Forest	EIS	Cal Energy	U.S. Forest Service Bureau of Land Management					Thermal Gradient Holes Exploration Drilling Exploratory Boreholes Production Wells
NV-020-07-EA-01	EA	Ormat Technologies Inc	Bureau of Land Management	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management	Drilling Techniques Observation Wells
NV-020-08-CX-65	CX	Ormat Technologies Inc	Bureau of Land Management	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management	Passive Seismic Techniques
NV-020-08-DNA-52	DNA	Gerlach Geothermal LLC	Bureau of Land Management	BLM Winnemucca District Office				Thermal Gradient Holes
NV-063-EA06-098	EA	Sierra Geothermal Power	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes Slim Holes
NV-EA-030-07-05	EA	Vulcan Power Company	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
NVN-084575	CU	Vulcan Power Company	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office			Reflection Survey Seismic Techniques
NVN-084629	CU	Vulcan Energy	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-084630	CU	Vulcan Energy	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Gravity Methods
NVN-086285	CU	Magma Energy	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-086286	CU	Magma Energy	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-086287	CU	Nevada Geothermal Power	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	2-M Probe Survey
NVN-086761	CU	Colado Project, LLC	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-086762	CU	Colado Project, LLC	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management
NVN-087388	CU	Enel North America	BLM Stillwater Field Office	BLM Carson City District Office	BLM Stillwater Field Office	BLM Stillwater Field Office	BLM Stillwater Field Office	Audio-Magnetotellurics
NVN-087791	CU	TGP Dixie Development Company	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-087809	CU	Oski Energy LLC	BLM Nevada State Office	BLM Carson City District Office	BLM Stillwater Field Office	BLM Stillwater Field Office	BLM Stillwater Field Office	Ground Gravity Survey
NVN-087811	CU	TGP Dixie Development Co	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-087812	CU	TGP Dixie Development Co	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Electrical Techniques
NVN-087930	CU	Magma Energy	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotelluric Techniques
NVN-088205	EA	Ormat Technologies Inc	BLM Stillwater Field Office	BLM Carson City District Office	BLM Stillwater Field Office	BLM Stillwater Field Office	BLM Stillwater Field Office	Thermal Gradient Holes Observation Wells Exploratory Well
NVN-088208	CU	Vulcan Power Company	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	BLM Stillwater Field Office	USFS Humboldt-Toiyabe National Forest	Ground Gravity Survey
NVN-088259	CU	Geothermal Technical Partners	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management
NVN-091276	CU	University of Nevada	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Water Sampling
NVN-091277	CU	Nevada Bureau of Mines and Geology	Bureau of Land Management	BLM Winnemucca District Office		Bureau of Land Management	Bureau of Land Management	Water Sampling
NVN-88321	CU	Stephen G. Muir	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Microgravity-Hybrid Microgravity
NVN-89274	CU	AltaRock Energy Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Geophysical Techniques
NVN-89275	CU	AltaRock Energy Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Geophysical Techniques
NVN-89276	CU	AltaRock Energy Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Geochemical Techniques
NVN-89278	CU	AltaRock Energy Inc	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Geophysical Techniques
NVN-89292	CU	Nevada Geothermal Power	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	2-M Probe Survey
NVN-89306	CU	Terra Gen Dixie Valley Development Co	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Magnetotellurics
NVN-89534	CU	Nevada Geothermal Power	BLM Nevada State Office	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Thermal Gradient Holes
USDA-FS-EA-NV-030-06-025 2007	EA	Vulcan Power Company Western Geothermal Partners	USFS Humboldt-Toiyabe National Forest
USDA-FS-EA-NV-030-06-025 2012	EA		USFS Humboldt-Toiyabe National Forest

Exploration References

^[1]

^[2]

^[3]

↑ ^1.0 ^1.1 "[http://www.geo-energy.org/reports/Factors%20Affecting%20Cost%20of%20Geothermal%20Power%20Development%20-%20August%202005.pdf Annual US Geothermal Power Production and Development Report]"
↑ ^2.0 ^2.1 ^2.2 "Developement of Metric for Measuring the Impact of RD&D Funding on GTO's Geothermal Exploration Goals"
↑ ^3.0 ^3.1 ^3.2 "[http://www.geo-energy.org/reports/Factors%20Affecting%20Cost%20of%20Geothermal%20Power%20Development%20-%20August%202005.pdf Factors Affecting Costs of Geothermal Power Development]"

[GEA-Development-1] 1.0 ^1.1 "[http://www.geo-energy.org/reports/Factors%20Affecting%20Cost%20of%20Geothermal%20Power%20Development%20-%20August%202005.pdf Annual US Geothermal Power Production and Development Report]"

[Jenne_Cost_Time-2] 2.0 ^2.1 ^2.2 "Developement of Metric for Measuring the Impact of RD&D Funding on GTO's Geothermal Exploration Goals"

[GEA_Cost_Factors-3] 3.0 ^3.1 ^3.2 "[http://www.geo-energy.org/reports/Factors%20Affecting%20Cost%20of%20Geothermal%20Power%20Development%20-%20August%202005.pdf Factors Affecting Costs of Geothermal Power Development]"

[1]

[2]

[3]

Geothermal/Exploration