Our Services

Geophysical Methods

We offer versatile technologies and methods tailored for a range of subsurface investigations.

Borehole Logging

Geophysical borehole logging, also known as well logging or wireline logging, can provide accurate data of the physical properties of geologic units within the borehole environment.  Borehole logging tools encompass a wide range of sensors to evaluate the in-situ formation in boreholes either cased or uncased.  Tools range from mechanical devices, nuclear/gamma, acoustical, electrical, imaging, and sensors for fluid properties. In all cases the system consists of the borehole tool that is manipulated up and down the borehole from a winch up to several hundred feet or more.

Common applications involve detailed mapping of fracture zones and their respective orientation, geologic characterization of rock types, fluid flow for groundwater evaluation of transmissive zones, contaminant or tracer detection, and rock properties. The borehole systems are highly portable and can be transported by logging vehicle, ATV, or flown into to remote sites if necessary.  Industry standard-WellCADTM Software is used for data display and interpretation of sensor data.  The software produces interpreted fracture orientation, log editing, analysis and presentation of all logging data.

Applications
  • Fracture density and orientation
  • Bed and aquifer thickness
  • Permeability and porosity estimates (transmissive zones)
  • Borehole fluid characterization
  • Borehole fluid flow rates
  • Casing integrity and well screen location
  • Mineral exploration
  • Groundwater exploration

More details HERE

 

Magnetic

Magnetometers measure the intensity of the earth's magnetic field regardless of direction (total field magnetometers), or the intensity in a certain direction (fluxgate magnetometers). Thanks to superior data collection speed and sensitivity, total field magnetometers are more commonly used for environmental applications. Only ferrous objects will cause fluctuations in the earth magnetic field and can therefore be detected with magnetometers.

Using two sensors, GEL teams can record the sensor readings and the magnetic gradient at the measurement location for increased sensitivity and data quality. We store and display the data on a digital data logger, and download the data to a laptop for thorough analysis and interpretation.

APPLICATIONS
  • Unexploded ordnance (UXO) mapping
  • Locating underground storage tanks (UST) and buried metal drums
  • Locating buried debris and landfills
  • Archaeological excavation to locate artifacts on construction sites and archaeological dig sites
  • Mineral exploration
  • Groundwater exploration

More details HERE.

 
Electromagnetic

Electromagnetic (EM) instruments utilize electromagnetic transmitters and receivers for the detection of subsurface metal and lateral and vertical variations in electrical conductivity. The EM instruments can detect both ferrous and non-ferrous metals. Some models, such as the EM61-MK2 by Geonics is relatively insensitive to interference from nearby surface metal such as fences, buildings, cars, etc., yet it detects a single 55-gallon drum at a depth of over 10 feet beneath the instrument.

With electromagnetic methods, data can be viewed by the operator for on-the-fly detection, or downloaded to a laptop for processing analysis, and mapping. The instruments transmit and receive signals by means of induction and do not require direct ground contact.

Applications
  • Locating Underground Storage Tanks (UST) and Buried Drums
  • Unexploded Ordnance (UXO) Mapping
  • Underground Utility Mapping
  • Locating Buried Debris, Landfills and Contaminants
  • Mineral Exploration
  • Groundwater exploration

More details HERE.

 
Seismic

Seismic methods involve the generation and recording of sound waves for detecting subsurface interfaces and measuring seismic velocity variations with depth, using geophones and a seismograph. The GEL team can make preliminary interpretations in the field then download data to a laptop for further processing and analysis.

Applications
  • Determining depth to and ripability of bedrock
  • Mapping fracture zones and karstic limestone
  • Locating and detecting buried foundations
  • Soil classification studies
  • Vibration monitoring

More details HERE.

 
Electrical Resistivity

We make resistivity measurements by introducing an electrical current into the earth between a pair of electrodes and measuring the potential electric current between a second pair of electrodes. A linear electrode array produces a 2D cross-section of the subsurface environment.

Applications
  • Delineating the depth, thickness, and lateral extent of geologic strata (sands and gravels associated with paleo-stream channels)
  • Locating geologic and structural anomalies
  • Mapping contaminant plumes
  • Locating and delineating landfills
  • Mapping subsurface voids and sinkholes

More details HERE.

 


Our Locations: Charleston, South Carolina; Raleigh, Charlotte, Asheville and Greensboro North Carolina; Marietta, Georgia and Jacksonville, Florida.  Visit our contact page for details.

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