Geothermal/Well Field

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Geothermal Well Fields and Reservoirs

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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.

TechniqueExploration
Group
Exploration
Sub Group
Lithology
Info Provided
Structure/Stratigraphic
Info Provided
Hydrologic
Info Provided
Thermal
Info Provided
2-M Probe SurveyField TechniquesData Collection and MappingIdentify and delineate shallow thermal anomalies
Acoustic LogsDownhole TechniquesWell Log Techniquesdetermine porosity of layersmap discontinuities to determine their orientation.
Active Seismic MethodsGeophysical TechniquesSeismic Techniques
Active Seismic TechniquesGeophysical TechniquesSeismic TechniquesRock 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 SensorsRemote Sensing TechniquesActive SensorsDetect fault and ground movement, delineate faults, create high-resolution DEMS, quantify fault kinemaics, develop lineament maps, Geophysical MonitoringCan give indications about subsurface geothermal fluid flow
Aerial PhotographyRemote Sensing TechniquesPassive Sensorsmap structures/faultsmap surface water featuresif photos taken in winter snow cover, can map thermal anomalies
Aeromagnetic SurveyGeophysical TechniquesMagnetic Techniquesmap structure, basin fill thickness, and magnetic mineral concentrations in ore bodies
Airborne Electromagnetic SurveyGeophysical TechniquesElectrical Techniquesprovide data on rock type and mineral contentcan be used to detect changes in density of fluids and indicate if there is salt water intrusion
Airborne Gravity SurveyGeophysical TechniquesGravity TechniquesDistribution 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 ModelingData and Modeling TechniquesModeling Techniques
Audio-MagnetotelluricsGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Borehole Seismic TechniquesDownhole TechniquesBorehole Seismic TechniquesRock unit density influences elastic wave velocitiesStructural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etcCombining compressional and shear wave results can indicate the presence of fluid saturation in the formationHigh temperatures and pressure impact the compressional and shear wave velocities
Caliper LogDownhole TechniquesWell Log Techniques
Cation GeothermometersGeochemical TechniquesGeochemical Data AnalysisUsed to estimate reservoir temperatures.
Cement Bond LogDownhole TechniquesWell Log Techniques
Chemical LoggingDownhole TechniquesWell Log TechniquesPresence and geochemical composition of fluid producing zonesCalcium-alkalinity ratios versus depth assist in defining warm and hot water aquifers
Compound and Elemental AnalysisLab Analysis TechniquesFluid Lab AnalysisResults can aid in the determination of fluid source regions and circulation pathways.Certain elements exhibit high spatial correlation with high-temperature geothermal systems.
Conceptual ModelData and Modeling TechniquesModeling TechniquesRock types, rock chemistry, stratigraphic layer organizationLocation and shape of permeable and non-permeable structures, faults, fracture patternsHydrothermal fluid flow characteristics, up-flow patternsTemperature and pressure extrapolation throughout reservoir, heat source characteristics
Controlled Source Audio MTGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Controlled Source Frequency-Domain MagneticsGeophysical TechniquesMagnetic TechniquesLocate geothermal groundwater and flow patterns.
Core AnalysisLab Analysis TechniquesRock Lab AnalysisCore 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 HolesDrilling TechniquesExploration DrillingCore holes are drilled to identify lithology and mineralizationRetrieved samples can be used to identify fracture networks or faultsThermal conductivity measurements can be done on retrieved samples.
Cross-Dipole Acoustic LogDownhole TechniquesWell Log TechniquesRock stress and fracture analysisUse for fracture identification in open and cased holes. Also used for evaluating hydro fracturing/well stimulation effectiveness.
Cuttings AnalysisLab Analysis TechniquesRock Lab AnalysisCuttings are used to define lithology
DC Resistivity Survey (Dipole-Dipole Array)Geophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
DC Resistivity Survey (Mise-A-La-Masse)Geophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
DC Resistivity Survey (Pole-Dipole Array)Geophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
DC Resistivity Survey (Schlumberger Array)Geophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
DC Resistivity Survey (Wenner Array)Geophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Data Acquisition-ManipulationData and Modeling TechniquesData Techniques
Data Collection and MappingField TechniquesData Collection and MappingLocates active faults in the area of interest. Map fault and fracture patterns, kinematic informationCan reveal whether faults are circulating hydrothermal fluids. Map surface manifestations of geothermal systems.Identify and delineate shallow thermal anomalies. Map surface temperature.
Data TechniquesData and Modeling TechniquesData Techniques
Data and Modeling TechniquesData and Modeling TechniquesRock types, rock chemistry, stratigraphic layer organizationStress fields and magnitudes, location and shape of permeable and non-permeable structures, faults, and fracture patternsVisualization and prediction of the flow patterns and characteristics of geothermal fluids, hydrothermal fluid flow characteristics, up-flow patternsThermal conduction and convection patterns in the subsurface, temperature and pressure extrapolation throughout reservoir, heat source characteristics
Density LogDownhole TechniquesWell Log Techniquesprovides data on the bulk density of the rock surrounding the wellStratigraphic correlation between well bores.Porosity of the formations loggesd can be calculated for the Density log andprovide an indication potential aquifers.
Development DrillingDrilling TechniquesDevelopment DrillingIdentify lithology and mineralization, provide core samples and rock cuttingsRetrieved 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 SurveyGeophysical TechniquesElectrical TechniquesRock 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 SamplingDownhole TechniquesWell Testing TechniquesWater 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 TechniquesDownhole TechniquesDetermination of lithology, grain sizeThickness and geometry of rock strata, fracture identificationPorosity, permeability, water saturationFormation temperature with depth
Drilling Methods
Drilling TechniquesDrilling TechniquesIdentify lithology and mineralization, provide core samples and rock cuttingsRetrieved 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 AnalysisDownhole TechniquesWell Testing TechniquesEnables estimation of in-situ reservoir elastic parameters.Enables estimation of in-situ reservoir hydraulic parameters.
Electrical Profiling ConfigurationsGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Electrical TechniquesGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Electromagnetic Profiling TechniquesGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Electromagnetic Sounding TechniquesGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Electromagnetic TechniquesGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Exploration DrillingDrilling TechniquesExploration DrillingIdentify lithology and mineralization, provide core samples and rock cuttingsRetrieved 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 BoreholesDrilling TechniquesExploration DrillingCan provide core or cuttingsIdentify 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 WellDrilling TechniquesExploration DrillingCan provide core or cuttingsIdentify 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
FLIRRemote Sensing TechniquesPassive SensorsMap surface temperatures
Fault MappingField TechniquesData Collection and MappingLocates active faults in the area of interestCan reveal whether faults are circulating hydrothermal fluids
Field MappingField TechniquesData Collection and MappingMap surface geology and hydrothermal alteration.Map fault and fracture patterns, kinematic information.Map surface manifestations of geothermal systems.Map surface temperature.
Field SamplingField TechniquesField SamplingRock 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 TechniquesField TechniquesLocates 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 TestDownhole TechniquesWell Testing TechniquesFlow 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 AnalysisLab Analysis TechniquesFluid Lab AnalysisFluid composition at a point in time and spaceThe minimum temperature of fluid inclusion formation
Fluid Lab AnalysisLab Analysis TechniquesFluid Lab AnalysisResults 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 TechniquesDownhole TechniquesFormation Testing Techniques
Frequency-Domain Electromagnetic SurveyGeophysical TechniquesElectrical TechniquesDetection of high-conductivity bodies in the subsurface.Detection of the presence of a thermal anomaly through its resistivity signature.
Gamma LogDownhole TechniquesWell Log Techniquesprovides information on changes in rock type near the wellbore from changes in measured gamma radiationusing multiple gamma logs over an area, the depth to the sandstone and shale layers can be correlated over larger areas
Gas Flux SamplingField TechniquesField SamplingHigh flux can be indicative of conduits for fluid flow.Anomalous flux is associated with active hydrothermal activity.
Gas GeothermometryGeochemical TechniquesGeochemical Data Analysis
Gas SamplingField TechniquesField SamplingHigh 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 AnalysisGeochemical TechniquesGeochemical Data Analysis
Geochemical TechniquesGeochemical Techniques
Geodetic SurveyRemote Sensing TechniquesPassive SensorsMap regional strain rates
Geographic Information SystemData and Modeling TechniquesData TechniquesAny mapable informationAny mapable informationAny mapable informationAny mapable information
Geophysical MethodsGeophysical TechniquesGeophysical Techniques
Geophysical TechniquesGeophysical Techniquesmay be inferredmay be inferredmay be inferredmay be inferred
Geothermal Literature ReviewData and Modeling TechniquesData Techniques
GeothermometryGeochemical TechniquesGeochemical Data Analysisused to estimate reservoir temperatures
Gravity MethodsGeophysical TechniquesGravity Techniques
Gravity TechniquesGeophysical TechniquesGravity TechniquesDistribution 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 TechniquesGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Ground Gravity SurveyGeophysical TechniquesGravity TechniquesDistribution 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 MagneticsGeophysical TechniquesMagnetic TechniquesPresence 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 SamplingField TechniquesField SamplingWater 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 TechniquesData Collection and MappingBulk and trace element analysis of rocks, minerals, and sediments.
HydroprobeDrilling TechniquesExploration DrillingCollection of ground water samples for geochemistry and geothermometryTemperature measurements down to 50 m
Hyperspectral ImagingRemote Sensing TechniquesPassive Sensorsmineral maps can be used to show the presence of hydrothermal minerals and mineral assemblagesaerial photographs can show structuresdelineate locations of surface water featuresvegetation maps can show plants stressed due to nearby thermal activity
Image LogsDownhole TechniquesWell Log TechniquesIdentify 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
InSARRemote Sensing TechniquesActive SensorsGeophysical MonitoringCan give indications about subsurface geothermal fluid flow
Injectivity TestDownhole TechniquesWell Testing TechniquesPermeability of the well
Isotope GeothermometryGeochemical TechniquesGeochemical Data Analysis
Isotopic Analysis- FluidLab Analysis TechniquesFluid Lab AnalysisWater rock interactionOrigin of hydrothermal fluids; Mixing of hydrothermal fluidsIsotopic ratios can be used to characterize and locate subsurface thermal anomalies.
Isotopic Analysis- RockLab Analysis TechniquesRock Lab AnalysisWater rock interaction
Lab Analysis TechniquesLab Analysis TechniquesWater 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 lithologyAnomalously 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 anisotropyReconstructing 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 spaceHigh 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
LiDARRemote Sensing TechniquesActive Sensorsdelineate faults,
create high-resolution DEMS,
quantify fault kinemaics,
develop lineament maps
Liquid GeothermometryGeochemical TechniquesGeochemical Data Analysis
Long-Wave InfraredRemote Sensing TechniquesPassive SensorsMap characteristic minerals associated with hot springs/mineral depositsMap surface temperatures
MacrophotographyField TechniquesData Collection and MappingIdentify and document surface geology and mineralogy
Magnetic TechniquesGeophysical TechniquesMagnetic TechniquesPresence 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 TechniquesGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
MagnetotelluricsGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Mercury VaporLab Analysis TechniquesFluid Lab AnalysisAnomalously high concentrations can indicate high permeability or conduit for fluid flowField wide soil sampling can generate a geometrical approximation of fluid circulationHigh concentration in soils can be indicative of active hydrothermal activity
Micro-EarthquakeGeophysical TechniquesSeismic TechniquesFault zones, permeable pathwaysFluid type- liquid or steam
Microgravity-Hybrid MicrogravityGeophysical TechniquesGravity TechniquesGround subsidence can be mapped using microgravityMonitoring net mass changes of a geothermal reservoir due to production and reinjection processesChanges in liquid density due to temperature changes in the reservoir
Microhole ArrayDrilling TechniquesExploration DrillingMay 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 TechniquesData and Modeling TechniquesModeling TechniquesRock types, rock chemistry, stratigraphic layer organizationStress fields and magnitudes, location and shape of permeable and non-permeable structures, faults, fracture patternsVisualization and prediction of the flow patterns and characteristics of geothermal fluids, hydrothermal fluid flow characteristics, up-flow patternsThermal conduction and convection patterns in the subsurface, temperature and pressure extrapolation throughout reservoir, heat source characteristics
Modeling-Computer SimulationsData and Modeling TechniquesModeling TechniquesStress fields and magnitudesVisualization and prediction of the flow patterns and characteristics of geothermal fluidsThermal conduction and convection patterns in the subsurface
Mud LoggingDownhole TechniquesWell Log TechniquesLithological layers are identified from drill cuttingsPorosity of rocksFluid content of the borehole while drilling can be determined
Multicomponent GeothermometersGeochemical TechniquesGeochemical Data Analysis
Multispectral ImagingRemote Sensing TechniquesPassive Sensorsrelative mineral mapsaerial photographs can show structuresdelineate locations of surface water featuresvegetation maps can show plants stressed due to nearby thermal activity
Near Infrared SurveysRemote Sensing TechniquesPassive Sensors
Neutron LogDownhole TechniquesWell Log Techniquesif used in conjunction with other logs, this technique can provide information on the rock type and the porosityCorelation of rock unitsEstimate of formation porosity
Numerical ModelingData and Modeling TechniquesModeling TechniquesStress fields and magnitudesVisualization and prediction of the flow patterns and characteristics of geothermal fluidsThermal conduction and convection patterns in the subsurface
Oblique Aerial & Ground Visible Band & Thermographic ImagingRemote Sensing TechniquesPassive Sensors
Observation WellsDrilling TechniquesDevelopment DrillingTotal dissolved solids, fluid pressure, flow rates, and flow directionMonitors temperature of circulating fluids
Over Core StressLab Analysis TechniquesRock Lab Analysis
PSInSARRemote Sensing TechniquesActive SensorsDetect fault and ground movementCan give indications about subsurface geothermal fluid flow
Paleomagnetic MeasurementsLab Analysis TechniquesRock Lab AnalysisCan determine detailed information about rock composition and morphologyHistoric structure and deformation of land
Passive Seismic TechniquesGeophysical TechniquesSeismic TechniquesRock 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 SensorsRemote Sensing TechniquesPassive SensorsMineral maps can be used to show the presence of hydrothermal minerals and mineral assemblagesMap structures/faults and regional strain ratesMap surface water featuresMap surface temperatures
Petrography AnalysisLab Analysis TechniquesRock Lab AnalysisProvides detailed information about rock composition and morphology
Portable X-Ray Diffraction (XRD)Field TechniquesData Collection and Mapping
Portfolio Risk ModelingData and Modeling TechniquesModeling Techniques
Pressure Temperature LogDownhole TechniquesWell Log TechniquesPerturbations in temperature or pressure can be indicative of faults or other structural featuresfluid cirulation, over-pressured zones, and under-pressured zones.Temperature profile with depth
Production WellsDrilling TechniquesDevelopment DrillingDrill cuttings are analyzed to determine lithology and mineralogyFractures, faults, and geologic formations that the well passes through are identified and mapped.Identify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistryDirect temperature measurements from within the reservoir
RadarRemote Sensing TechniquesActive SensorsDetect fault and ground movementCan give indications about subsurface geothermal fluid flow
RadiometricsRemote Sensing TechniquesPassive SensorsPrimary use is in mapping potassium alterations
Reflection SurveyGeophysical TechniquesSeismic TechniquesRock 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 SurveyGeophysical TechniquesSeismic TechniquesRock unit density influences elastic wave velocities.Can provide information on crustal thickness, depth to basement.
Remote Sensing TechniquesRemote Sensing Techniques
Rock DensityLab Analysis TechniquesRock Lab AnalysisDensity of different lithologic units.
Rock Lab AnalysisLab Analysis TechniquesRock Lab AnalysisCore 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 SamplingField TechniquesField SamplingRock 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.
SARRemote Sensing TechniquesActive Sensorscreate high-resolution DEMs,
detect fault and ground movement
SRTRemote Sensing TechniquesActive Sensorshigh-resolution DEMs
SWIRRemote Sensing TechniquesPassive Sensorsmap characteristic minerals associated with hot springs/mineral deposits
Seismic TechniquesGeophysical TechniquesSeismic TechniquesRock 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 PotentialGeophysical TechniquesElectrical TechniquesSP 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 GeothermometersGeochemical TechniquesGeochemical Data AnalysisUsed to estimate reservoir temperatures.
Single-Well And Cross-Well Seismic ImagingDownhole TechniquesBorehole Seismic TechniquesRock 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 ResistivityDownhole TechniquesWell Log TechniquesIdentify 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 waterResistivity influenced by temperature
Slim HolesDrilling TechniquesExploration DrillingIf core is collectedIf core is collectedFluid flow and water chemistryThermal gradient or bottom hole temperature
Soil Gas SamplingField TechniquesField SamplingIdentify concealed faults that act as conduits for hydrothermal fluids.Identify hydrothermal gases of magmatic origin.Differentiate between amagmatic or magmatic sources heat.
Soil SamplingField TechniquesField SamplingCan reveal relatively high permeability zonesUsed to locate active hydrothermal systems
Spontaneous Potential Well LogDownhole TechniquesWell Log TechniquesSP 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.
SqueeSARRemote Sensing TechniquesActive SensorsDetect fault and ground movementCan give indications about subsurface geothermal fluid flow
Static Temperature SurveyDownhole TechniquesWell Testing TechniquesExtrapolate the true temperature of the formation the well penetrates
Step-out WellDrilling TechniquesExploration DrillingDrill cuttings are analyzed to determine lithology and mineralogyFractures, faults, and geologic formations that the well passes through are identified and mappedIdentify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistryDirect temperature measurements from within the reservoir
Stereo Satellite ImageryRemote Sensing TechniquesPassive Sensorsmap structures/faultsmap surface water features, determine the boundary conditions of hydrothermal circulation
Stress TestDownhole TechniquesWell Testing TechniquesFracture distribution and ambient tectonic stressesFluid flow direction
Surface Gas SamplingField TechniquesField SamplingGas composition and source of fluids.Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures.
Surface Water SamplingField TechniquesField SamplingWater composition and source of fluidsWater temperature
Teleseismic-Seismic MonitoringGeophysical TechniquesSeismic TechniquesRock 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 SurveyGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Thermal Gradient HolesDrilling TechniquesExploration DrillingField wide fluid flow characteristics if an array of wells are drilledMapping and projecting thermal anomalies
Thermal Ion DispersionGeochemical TechniquesGeochemical Data Analysis
ThermochronometryGeochemical TechniquesGeochemical Data AnalysisThermal history of area, rate of cooling, age that minerals reached closure temperature
Time-Domain ElectromagneticsGeophysical TechniquesElectrical TechniquesDetection 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 AnalysisLab Analysis TechniquesFluid Lab AnalysisReconstructing the fluid circulation of a hydrothermal system
Tracer TestingDownhole TechniquesWell Testing TechniquesFracture zones and formation permeabilityFlow rates, flow direction, hydrologic connections, storativity
Vertical Electrical Sounding ConfigurationsGeophysical TechniquesElectrical TechniquesRock composition, mineral and clay contentDetection of permeable pathways, fracture zones, faultsResistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore waterResistivity influenced by temperature
Vertical Flowmeter TestDownhole TechniquesWell Testing TechniquesDefine permeable zones within a well
Vertical Seismic ProfilingDownhole TechniquesBorehole Seismic TechniquesRock 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 SamplingField TechniquesField SamplingWater composition and source of fluidsWater temperature
Well DeepeningDrilling TechniquesDevelopment DrillingDrill cuttings are analyzed to determine lithology and mineralogyFractures, faults, and geologic formations that the well passes through are identified and mapped.Identify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistryDirect temperature measurements from within the reservoir
Well Log TechniquesDownhole TechniquesWell Log Techniquesdepth and thickness of formations; lithology and porosity can be inferredreservoir thickness, reservoir geometry, borehole geometrypermeability and fluid composition can be inferreddirect temperature measurements; thermal conductivity and heat capacity
Well Testing TechniquesDownhole TechniquesWell Testing TechniquesEnable estimation of in-situ reservoir elastic parametersFracture distribution, formation permeability, and ambient tectonic stressesprovides 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 TechniquesRock Lab Analysis
X-Ray Fluorescence (XRF)Lab Analysis TechniquesRock Lab AnalysisBulk and trace element analysis of rocks, minerals, and sediments.
Z-Axis Tipper ElectromagneticsGeophysical TechniquesElectrical 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
ApplicantLead
Agency
District
Office
Field
Office
Mineral
Manager
Surface
Manager
Techniques
CA-96062042EISCalpine CorporationUSFS
DOE-EA-1116EAExergy, Inc.DOEGolden Field OfficeGolden Field Office
DOE-EA-1733EACalpineUnited States Department of EnergyGolden Field OfficeGolden Field OfficeState of California
DOE-EA-1849EAOrmat Technologies IncUnited States Department of EnergyGolden Field OfficeBLM
DOE-EIS-0298EISCalEnergy GenerationUnited States Department of Energy
Bonneville Power Admin
BLM
USFS
BLMBLM
DOI-BLM-CA-017-05-051EAMammoth PacificBLMBLM Bishop Field OfficeBLM Bishop Field OfficeBLMBLM Bishop Field Office
DOI-BLM-CA-017-P006-60EISPacific EnergyBLMBLM Central California District OfficeBLM Bishop Field OfficeDevelopment Drilling
DOI-BLM-CA-670-2010-107CXOrmat Nevada, Inc.BLMBLM California Desert District OfficeBLMBLMProduction Wells
DOI-BLM-CA-C050-2009-0005-EAEAAltaRock Energy IncBureau of Land ManagementBLM Central California District OfficeBLM Ukiah Field OfficeBureau of Land ManagementBureau of Land ManagementDevelopment Drilling
DOI-BLM-CA-EA-2002-???EACalpine Corporation (Calpine) and CPN Telephone Flat Inc. (CPN)BLMBLMBLMExploration Drilling
Thermal Gradient Holes
DOI-BLM-NM-L000-2012-0200-DNADNALightning Dock Geothermal IncBureau of Land ManagementBLM Las Cruces District OfficeBLMDrilling Techniques
DOI-BLM-NV-C010-2009-0018-EAEAMagma EnergyBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBLMBureau of ReclamationProduction Wells
DOI-BLM-NV-C010-2010-0016-EAEAVulcan Power CompanyBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Reclamation
Nevada
Airborne Electromagnetic Survey
DOI-BLM-NV-C010-2011-0501-EAEAGradient ResourcesBLMBLM Carson City District OfficeBLM Sierra Front Field Office
BLM Stillwater Field Office
BLMBLM
Bureau of Reclamation
Well Testing Techniques
Development Drilling
Exploration Drilling
DOI-BLM-NV-C010-2011-0514-EAEAMagma EnergyBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land Management
DOI-BLM-NV-C010-2011-0516-EAEAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementDrilling Techniques
Thermal Gradient Holes
DOI-BLM-NV-C010-2012-0005-DNADNAMagma EnergyBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2012-0016-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementProduction Wells
DOI-BLM-NV-C010-2012-0019-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2012-0020-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2012-0028-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementFlow Test
Injectivity Test
DOI-BLM-NV-C010-2012-0029-EAEAOrmat Technologies IncBLMBLM Carson City District OfficeBLM Stillwater Field OfficeBLMBLMDownhole Techniques
Well Testing Techniques
Drilling Techniques
Exploration Drilling
DOI-BLM-NV-C010-2012-0035-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementPressure Temperature Log
DOI-BLM-NV-C010-2012-0046-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2012-0048-DNADNAEnel Salt Wells LLCBLM Nevada State OfficeBLM Carson City District OfficeBLM Stillwater Field OfficeBLMObservation Wells
DOI-BLM-NV-C010-2012-0050-EAEAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementDrilling Techniques
Development Drilling
DOI-BLM-NV-C010-2012-0058-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2012-0068-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2012-0073-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2013-0007-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2013-0020-DNADNAGradient Resources Geothermal Drilling Permit Application Well 14-28Bureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBLMBureau of ReclamationProduction Wells
DOI-BLM-NV-C010-2013-0023-DNADNAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-NV-C010-2013-0026-DNADNATGP Coyote Canyon LLCBLMBLM Carson City District OfficeBLM Stillwater Field OfficeBLMBLMProduction Wells
DOI-BLM-NV-C010-2013-0037-DNADNAORNI 47 LLCBLMBLM Carson City District OfficeBLM Stillwater Field OfficeBLMBLMDrilling Methods
DOI-BLM-NV-CO10-2011-0501-EAEAGradient ResourcesBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBLMProduction Wells
Thermal Gradient Holes
DOI-BLM-NV-W010-2011-0001-EAEAOrmat Technologies IncBLMBLM Winnemucca District OfficeBLM Humboldt River Field OfficeBLMBLMWell Testing Techniques
Development Drilling
Exploration Drilling
DOI-BLM-NV-W010-2012-0057-EAEABrady Power PartnersBureau of Land ManagementBLM Winnemucca District OfficeBLM Humboldt River Field OfficeBureau of Land ManagementBureau of Land ManagementDownhole Techniques
DOI-BLM-NV-W010–2012–0005–EAEATerra-Gen Power LLCBLMBLM Winnemucca District OfficeBLM Humboldt River Field OfficeBLMBLMDownhole Techniques
Development Drilling
DOI-BLM-NV-W030-2012-0011-DNADNAUS Geothermal IncBureau of Land ManagementBLM Winnemucca District OfficeBureau of Land ManagementBureau of Land ManagementObservation Wells
DOI-BLM-OR-P000-2011-0003-EAEADavenport Power LLCBLMBLM Prineville District OfficeBureau of Land ManagementUnited States Forest ServiceDrilling Techniques
DOI-BLM-OR-V040-2011-0008-EAEAUS Geothermal IncBureau of Land ManagementBLM Vale District OfficeBLMBLMWell Testing Techniques
Development Drilling
DOI-BLM-UT-W020-2010-0042-EAEAOrmat Technologies IncBureau of Land ManagementBLM West Desert District OfficeBureau of Land ManagementBureau of Land ManagementThermal Gradient Holes
EA for Well Field Development at Patua Geothermal Area - DOI-BLM-NV-C010-2011-00016-EAEAGradient ResourcesBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBureau of Land Management
Bureau of Reclamation
Drilling Techniques
Exploratory Well
Thermal Gradient Holes
EA-NV-030-07-006EAOrmat Technologies IncBureau of Land ManagementBLM Carson City District OfficeBLM Stillwater Field OfficeBureau of Land ManagementBLM
Bureau of Reclamation
Exploration Drilling
Slim Holes
Thermal Gradient Holes
NEPA Process for Geothermal Power Plants in the Deschutes National ForestEISCal EnergyUSFS
BLM
Exploration Drilling
Exploratory Boreholes
Production Wells
Thermal Gradient Holes
NV-020-07-EA-01EAOrmat Technologies IncBLMBLM Winnemucca District OfficeBLMBLMDrilling Techniques
Observation Wells
San Emido Geothermal Energy North ProjectEAUSG Nevada LLCBLMBLM Winnemucca District OfficeBLMBLMProduction Wells