3-D Geologic Controls of Hydrothermal Fluid Flow at Brady Geothermal Field, Nevada using PCA
In many hydrothermal systems, fracture permeability along faults provides pathways for groundwater to transport heat from depth. Faulting generates a range of deformation styles that cross-cut heterogeneous geology, resulting in complex patterns of permeability, porosity, and hydraulic conductivity. Vertical connectivity (a through going network of permeable areas that allows advection of heat from depth to the shallow subsurface) is rare and is confined to relatively small volumes that have highly variable spatial distribution. This local compartmentalization of connectivity represents a significant challenge to understanding hydrothermal circulation and for exploring, developing, and managing hydrothermal resources. Here, we present an evaluation of the geologic characteristics that control this compartmentalization in hydrothermal systems through 3-D analysis of the Brady geothermal field in western Nevada. A published 3-D geologic map of the Brady area is used as a basis to develop structural and geological variables that are hypothesized to control or effect permeability or connectivity. The 3-D distribution of these variables is compared to the distribution of productive and non-productive fluid flow intervals along production wells and non-productive wells via principal component analysis (PCA). This comparison elucidates which geologic and structural variables are most closely associated with productive fluid flow intervals. Results indicate that production intervals at Brady are located: (1) within or near to known and stress-loaded macro-scale faults, and (2) in areas of high fault and fracture density.
This submission includes the published journal article detailing this work, the published 3-D geologic map of the Brady Geothermal Area used as a basis to develop structural and geological variables that are hypothesized to control or effect permeability or connectivity, 3-D well data, along which geologic data were sampled for PCA analyses, and associated metadata file. This work was done using existing R programs.
Complete Metadata
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| description | In many hydrothermal systems, fracture permeability along faults provides pathways for groundwater to transport heat from depth. Faulting generates a range of deformation styles that cross-cut heterogeneous geology, resulting in complex patterns of permeability, porosity, and hydraulic conductivity. Vertical connectivity (a through going network of permeable areas that allows advection of heat from depth to the shallow subsurface) is rare and is confined to relatively small volumes that have highly variable spatial distribution. This local compartmentalization of connectivity represents a significant challenge to understanding hydrothermal circulation and for exploring, developing, and managing hydrothermal resources. Here, we present an evaluation of the geologic characteristics that control this compartmentalization in hydrothermal systems through 3-D analysis of the Brady geothermal field in western Nevada. A published 3-D geologic map of the Brady area is used as a basis to develop structural and geological variables that are hypothesized to control or effect permeability or connectivity. The 3-D distribution of these variables is compared to the distribution of productive and non-productive fluid flow intervals along production wells and non-productive wells via principal component analysis (PCA). This comparison elucidates which geologic and structural variables are most closely associated with productive fluid flow intervals. Results indicate that production intervals at Brady are located: (1) within or near to known and stress-loaded macro-scale faults, and (2) in areas of high fault and fracture density. This submission includes the published journal article detailing this work, the published 3-D geologic map of the Brady Geothermal Area used as a basis to develop structural and geological variables that are hypothesized to control or effect permeability or connectivity, 3-D well data, along which geologic data were sampled for PCA analyses, and associated metadata file. This work was done using existing R programs. |
| distribution |
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"title": "Geothermics Journal Article",
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"accessURL": "https://doi.org/10.1016/j.geothermics.2021.102112",
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"description": "Link to journal article that details the PCA work. This article presents an evaluation of the geologic characteristics that control this compartmentalization in hydrothermal systems through 3-D analysis of the Brady geothermal field in western Nevada. "
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"title": "3-D Geologic Map of the Brady Geothermal Area",
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"description": "3-D geologic map characterizing the subsurface in the Brady geothermal area in the northern Hot Springs Mountains of northwestern Nevada that was used as a basis to develop structural and geological variables that are hypothesized to control or effect permeability or connectivity. The 3-D map was built by integrating the results from detailed geologic mapping, seismic-reflection, potential-field-geophysical, and lithologic well-logging investigations completed in the study area. This effort was undertaken to investigate the geologic structure in the geothermal field and geologic controls on hydrothermal circulation."
},
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"title": "All Brady 3-D Wells used for PCA.txt",
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"description": "Brady 3-D Wells digital dataset, along which geologic data were sampled for PCA analyses. This dataset includes well ID, depth, azimuth, inclination, location, dilation, coulomb stress, fault density, model temperature, and other fields."
},
{
"@type": "dcat:Distribution",
"title": "All Brady 3-D Wells used for PCA Metadata.txt",
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"accessURL": "https://gdr.openei.org/files/1345/AllBradyWells_PCA_metadata%20%281%29.txt",
"mediaType": "text/plain",
"description": "Metadata file for the Brady 3-D Wells digital dataset, along which geologic data were sampled for PCA analyses. This metadata file includes citation information, an abstract, the intended purpose of the data, time span of the data, spatial domain, use constraints, and other useful information."
}
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|
| DOI | 10.15121/1832132 |
| identifier | https://data.openei.org/submissions/7461 |
| issued | 2021-10-01T06:00:00Z |
| keyword |
[
"3D geologic model",
"3D well data",
"BHS",
"Brady",
"Brady Hot Springs",
"ML",
"PCA",
"R",
"characterization",
"code",
"energy",
"faults",
"geologic model",
"geologic structure",
"geology",
"geophysics",
"geothermal",
"geothermic",
"hydrothermal",
"machine learning",
"principal component analysis",
"production",
"stress",
"unsupervised"
]
|
| landingPage | https://gdr.openei.org/submissions/1345 |
| license | https://creativecommons.org/licenses/by/4.0/ |
| modified | 2021-11-23T16:27:11Z |
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|
| projectLead | Mike Weathers |
| projectNumber |
"35517"
|
| projectTitle | Insightful Subsurface Characterizations and Predictions |
| publisher |
{
"name": "United States Geological Survey",
"@type": "org:Organization"
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| spatial |
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|
| title | 3-D Geologic Controls of Hydrothermal Fluid Flow at Brady Geothermal Field, Nevada using PCA |
