Controlled Source Frequency-Domain Magnetics

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Exploration Technique: Controlled Source Frequency-Domain Magnetics

Exploration Technique Information
Exploration Group: Geophysical Techniques
Exploration Sub Group: Magnetic Techniques
Parent Exploration Technique: Magnetic Techniques
Information Provided by Technique
Hydrological: Locate geothermal groundwater and flow patterns.
Cost Information
Low-End Estimate (USD): 12,000.001,200,000 centUSD
12 kUSD
0.012 MUSD
1.2e-5 TUSD
/ mile
Median Estimate (USD): 18,000.001,800,000 centUSD
18 kUSD
0.018 MUSD
1.8e-5 TUSD
/ mile
High-End Estimate (USD): 25,000.002,500,000 centUSD
25 kUSD
0.025 MUSD
2.5e-5 TUSD
/ mile
Time Required
Low-End Estimate: 1 days0.00274 years
24 hours
0.143 weeks
0.0329 months
/ job
Median Estimate: 11 days0.0301 years
264 hours
1.571 weeks
0.361 months
/ job
High-End Estimate: 56 days0.153 years
1,344 hours
8 weeks
1.84 months
/ job
Additional Info
Cost/Time Dependency: Location, Size, Resolution, Terrain, Weather
Controlled Source Frequency-Domain Magnetics:
AquaTrackTM, a controlled-source frequency domain magnetics tool (CS-FDM), is a patented invention by Willowstick Technologies. This technique is meant to characterize groundwater conditions and flow patterns up to 1,000 m depth.
Other definitions:Wikipedia Reegle

Use in Geothermal Exploration
“Geologic and hydrologic features alter the alignment of the magnetic field generated by the CS-FDM energy introduced into the ground and where the energy propagates. When this energy crosses a geologic boundary it results in a change of the subsurface electrical properties. Additionally, the fluctuation in the flow of energy in the ground results in orientation changes in the magnetic field. Evaluating the magnetic field components of the CSFDM data provides an indication of areas where groundwater changes occur and where groundwater structures can be delineated.” [1]

Data Access and Acquisition
“CS-FDM uses a low voltage, low amperage audio frequency electrical current to energize the groundwater of interest. Electrodes are placed in strategic locations to facilitate contact with the groundwater. An alternating current with a specific signature frequency is applied to the electrodes. The resulting alternating current, flowing between the electrodes, follows the groundwater along preferential flow paths. Because groundwater is generally the best conductor in a given area, the electrical current concentrates in the groundwater between the strategically placed electrodes. As the electrical current flows through the groundwater in the area of investigation, it creates a magnetic field characteristic of the injected electrical current. This unique magnetic field is identified and surveyed from the surface of the ground where magnetic field measurements are recorded. The locations of the field measurement stations are identified using a Global Positioning System (GPS). The measured magnetic field data are then processed and correlated to other hydrogeologic data to bring together an enhanced groundwater model.” [1]


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