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Geothermal Well Fields and Reservoirs

Geothermal energy plant at The Geysers near Santa Rosa in Northern California, the world's largest electricity-generating hydrothermal geothermal development. Copyright © 1995 Warren Gretz

Geothermal Well Fields discussion


Groups of Well Field Techniques

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


Full List of Well Field Techniques


Reservoir Maintenance

Dictionary.png
Hydrothermal Reservoir:
Hydrothermal Reservoirs are underground zones of porous rock containing hot water and steam, and can be naturally occurring or human-made.
Other definitions:Wikipedia Reegle


Reservoir maintenance is an important aspect of geothemral power production. More here ...





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 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.
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
-Fluid pressures can be used to estimate flow rates
-Temperatures can be measured within the hole
-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
-Fluid pressures can be used to estimate flow rates
-Temperatures can be measured within the hole
-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 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.
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.
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
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 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
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

Geothermal Regulations and Permitting for Well Fields

For information about regulations and permitting related to geothermal project well fields, see the Regulatory and Permitting Information Desktop Toolkit.

Document # Analysis
Type
Applicant Lead
Agency
District
Office
Field
Office
Mineral
Manager
Surface
Manager
Techniques
CA-96062042 EIS Calpine Corporation USFS
DOE-EA-1116 EA Exergy, Inc. DOE DOE Golden Field Office DOE Golden Field Office
DOE-EA-1733 EA Calpine United States Department of Energy DOE Golden Field Office DOE Golden Field Office State of California
DOE-EA-1849 EA Ormat Technologies Inc United States Department of Energy DOE Golden Field Office BLM
DOE-EIS-0298 EIS CalEnergy Generation Bonneville Power Admin
BLM
USFS
United States Department of Energy
BLM BLM
DOI-BLM-CA-017-05-051 EA Mammoth Pacific BLM BLM Bishop Field Office BLM Bishop Field Office BLM BLM Bishop Field Office
DOI-BLM-CA-017-P006-60 EIS Pacific Energy BLM BLM Central California District Office BLM Bishop Field Office Development Drilling
DOI-BLM-CA-670-2010-107 CX Ormat Nevada, Inc. BLM BLM California Desert District Office BLM BLM Production Wells
DOI-BLM-CA-C050-2009-0005-EA EA AltaRock Energy Inc Bureau of Land Management BLM Central California District Office BLM Ukiah Field Office Bureau of Land Management Bureau of Land Management Development Drilling
DOI-BLM-CA-EA-2002-??? EA Calpine Corporation (Calpine) and CPN Telephone Flat Inc. (CPN) BLM BLM BLM Exploration Drilling
Thermal Gradient Holes
DOI-BLM-NM-L000-2012-0200-DNA DNA Lightning Dock Geothermal Inc Bureau of Land Management BLM Las Cruces District Office BLM Drilling Techniques
DOI-BLM-NV-C010-2009-0018-EA EA Magma Energy Bureau of Land Management BLM Carson City District Office BLM Stillwater Field Office BLM Bureau of Reclamation Production Wells
DOI-BLM-NV-C010-2010-0016-EA EA Vulcan Power Company Bureau of Land Management BLM Carson City District Office BLM Stillwater Field Office Bureau of Land Management Bureau of Reclamation
Nevada
Airborne Electromagnetic Survey
DOI-BLM-NV-C010-2011-0501-EA EA Gradient Resources BLM BLM Carson City District Office BLM Stillwater Field Office
BLM Sierra Front Field Office
BLM BLM
Bureau of Reclamation
Development Drilling
Exploration Drilling
Well Testing Techniques
DOI-BLM-NV-C010-2011-0514-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
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 Drilling Techniques
Thermal Gradient Holes
DOI-BLM-NV-C010-2012-0005-DNA DNA Magma Energy Bureau of Land Management BLM Carson City District Office BLM Stillwater Field Office Bureau of Land Management Bureau of Land Management Observation Wells
DOI-BLM-NV-C010-2012-0016-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 Production Wells
DOI-BLM-NV-C010-2012-0019-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 Observation Wells
DOI-BLM-NV-C010-2012-0020-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 Observation Wells
DOI-BLM-NV-C010-2012-0028-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 Flow Test
Injectivity Test
DOI-BLM-NV-C010-2012-0029-EA EA Ormat Technologies Inc BLM BLM Carson City District Office BLM Stillwater Field Office BLM BLM Downhole Techniques
Drilling Techniques
Exploration Drilling
Well Testing Techniques
DOI-BLM-NV-C010-2012-0035-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 Pressure Temperature Log
DOI-BLM-NV-C010-2012-0046-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 Observation Wells
DOI-BLM-NV-C010-2012-0048-DNA DNA Enel Salt Wells LLC BLM Nevada State Office BLM Carson City District Office BLM Stillwater Field Office BLM Observation Wells
DOI-BLM-NV-C010-2012-0050-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 Development Drilling
Drilling Techniques
DOI-BLM-NV-C010-2012-0058-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 Observation Wells
DOI-BLM-NV-C010-2012-0068-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 Observation Wells
DOI-BLM-NV-C010-2012-0073-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 Observation Wells
DOI-BLM-NV-C010-2013-0007-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 Observation Wells
DOI-BLM-NV-C010-2013-0020-DNA DNA Gradient Resources Geothermal Drilling Permit Application Well 14-28 Bureau of Land Management BLM Carson City District Office BLM Stillwater Field Office BLM Bureau of Reclamation Production Wells
DOI-BLM-NV-C010-2013-0023-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 Observation Wells
DOI-BLM-NV-C010-2013-0026-DNA DNA TGP Coyote Canyon LLC BLM BLM Carson City District Office BLM Stillwater Field Office BLM BLM Production Wells
DOI-BLM-NV-C010-2013-0037-DNA DNA ORNI 47 LLC BLM BLM Carson City District Office BLM Stillwater Field Office BLM BLM Drilling Methods
DOI-BLM-NV-CO10-2011-0501-EA EA Gradient Resources Bureau of Land Management BLM Carson City District Office BLM Stillwater Field Office BLM Thermal Gradient Holes
Production Wells
DOI-BLM-NV-W010-2011-0001-EA EA Ormat Technologies Inc BLM BLM Winnemucca District Office BLM Humboldt River Field Office BLM BLM Development Drilling
Exploration Drilling
Well Testing Techniques
DOI-BLM-NV-W010-2012-0057-EA EA Brady Power Partners Bureau of Land Management BLM Winnemucca District Office BLM Humboldt River Field Office Bureau of Land Management Bureau of Land Management Downhole Techniques
DOI-BLM-NV-W010–2012–0005–EA EA Terra-Gen Power LLC BLM BLM Winnemucca District Office BLM Humboldt River Field Office BLM BLM Development Drilling
Downhole Techniques
DOI-BLM-NV-W030-2012-0011-DNA DNA US Geothermal Inc Bureau of Land Management BLM Winnemucca District Office Bureau of Land Management Bureau of Land Management Observation Wells
DOI-BLM-OR-P000-2011-0003-EA EA Davenport Power LLC BLM BLM Prineville District Office Bureau of Land Management United States Forest Service Drilling Techniques
DOI-BLM-OR-V040-2011-0008-EA EA US Geothermal Inc Bureau of Land Management BLM Vale District Office BLM BLM Development Drilling
Well Testing Techniques
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
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
Drilling Techniques
Exploratory Well
Thermal Gradient Holes
EA-NV-030-07-006 EA Ormat Technologies Inc Bureau of Land Management BLM Carson City District Office BLM Stillwater Field Office Bureau of Land Management BLM
Bureau of Reclamation
Exploration Drilling
Slim Holes
Thermal Gradient Holes
NEPA Process for Geothermal Power Plants in the Deschutes National Forest EIS Cal Energy USFS
BLM
Exploration Drilling
Exploratory Boreholes
Production Wells
Thermal Gradient Holes
NV-020-07-EA-01 EA Ormat Technologies Inc BLM BLM Winnemucca District Office BLM BLM Drilling Techniques
Observation Wells
San Emido Geothermal Energy North Project EA USG Nevada LLC BLM BLM Winnemucca District Office BLM BLM Production Wells