HGI’s Geotection Monitoring\LDM System

HGI’s GeotectionTM Resistivity Monitoring\LDM System was designed to act as both a long term monitoring and rapid acquisition system for tracking subsurface fluid, contaminants, and heat movement in variable saturated media.  Our system provides rapid data acqusition, meets stringent UL/NEC electrical safety and can be expanded in blocks of 60 channels.  A three block, 180 channel system is most common.

Click Thumbnail at right to see HGI’s “Surface Geophysical Exploration” technology  featured in the July 29 issue of ‘Solutions’, a weekly publication of highlights and progress of the Hanford Tank Operations Contractor, Washington River Protection Solutions (WRPS).




Geotection is particularly suitable for:

  1. Leak detection from containment systems (underground storage tanks, levees and dams, landfills, pond liners, etc)
  2. Monitoring underground injections for enhanced oil/mineral recovery
  3. Monitoring the efficacy of remediation designs
  4. Assessing geohazards from flooding, drought, and landslides
  5. Reservoir monitoring
  6. Hydraulic fracturing


hydroGEOPHYSICS, Inc. (HGI) and Columbia Energy, Inc.  are pleased to introduce our latest resistivity data acquisition system called Geotection.  This trailer mounted system uses the electrical resistivity geophysical method to detect and monitor subtle changes within the subsurface that may indicate the presence of and-or movement of fluid within the subsurface.  Currently, our system can sample 180 channels of simultaneous data, making it the fastest resistivity data acquisition system on the market.  Geotection incorporates over 30 years of experience from a diverse project base that’s extends from mineral exploration and mining to environmental characterization and remediation.

Standard features include a completely modular design (making maintenance and upgrades fast and cost effective), self-diagnostics systems, remote and autonomous operation, and electrical noise suppression systems that allow performance on complex industrial sites.  Geotection consists of a mobile, trailer-based enclosure that can be temporarily or permanently deployed at a project site using mains or generator power.  Climate controls and satellite communication systems allow deployment in remote and harsh environments. In addition, Geotection is one of the few resistivity systems with UL/NEC compliance and our system was designed and fabricated under a NQA-1 quality assurance program.

Geotection Trailer Climate Controlled Operating Station.


Geotection breaks the traditional resistivity paradigm by accommodating investigations needing:

  • High temporal and spatial resolution
  • Near real-time information on solution migration
  • Modularity
  • Full control over acquisition parameters
  • Remote operations
  • Internal climate control
  • Power from generator or AC
  • Safety alarms with SMS messaging
  • Enough leg room to work, eat, and sleep

At 180 channels, the system promises a full measurement sweep in less than 20 minutes (with the pole-pole array, producing 32,220 voltage values).

Geotection Trailer



HGI produces full UL-compliant resistivity acquisition systems capable of long-term monitoring on federal properties.  Quality assurance also accompanies Geotection through full and complete drawing sets, auditable software, and NIST-traceable calibration.

The hardware, mounted in a shock-resistant rack, was designed to accommodate rugged field use and its modular design lends for quick and easy repair with no need to leave the survey site.

  • Current transmission boards feature robust mechanical relays with proven reliability.  Power output rated for 800W with full control over waveforms, stacking, duty cycle, and contact resistance thresholds.
  • Channel-specific tunable signal conditioning boards ensures the cleanest data possible.  Data acquisition provided by National Instruments PCI cards.  SP corrections.


  • Controlled by Labview – by running Labview, an industry leading software control system, customized acquisition software can be created to ensure relevant parameters are measured and recorded.  Also features an intuitive sequencing of electrode combinations with multiple sequence files running in an order set by the user based on priority.  Data are written to a database for easy access, real-time plotting, and extraction for inverse modeling.


HGI strives for high data quality, exacting measurements, and repeatability in resistivity acquisition.  A demonstration is presented below, comparing data acquired with Geotection to a leading industry standard for resistivity acquisition – the AGI SuperSting R8.  The two datasets are on average less than 8% different from each other.  Repeatability tests of Geotection data consistently reveal a coefficient of variation (COV) of around 0.005 ohms.

Results of comparing data acquired with Geotection to a leading industry standard for resistivity acquisition – the AGI SuperSting R8.

Example – Case Study

High quality resistivity data acquired from Geotection during a pressurized injection monitoring project were inverse modeled to produce volumetric images of solution coverage.  The image below shows the progression of fluid movement at four different times during the injection at a depth of 110 feet.  Directionality of solution movement was confirmed by monitoring a decreasing contact resistance in the borehole electrodes.

Results of data acquired with Geotection during a pressurized injection monitoring project. The data were inverse modeled to produce volumetric images of solution coverage. This image shows the progression of fluid movement at four different times during the injection at a depth of 110 feet.



Click here to View/Download Geotection technical specifications PDF.



Measurement modes

Apparent resistivity, resistance, self-potential, contact resistance, transmitter current and voltage, receiver voltage, weather (in/out temp, rain, wind, humidity)

Measurement range

(input voltage)

+/- 10 Volts

Measurement resolution

16-bit (305 microvolts per +/- 10 volt full-scale range) to (6.1 microvolts per +/- 0.2 volt full-scale range)


0.05% in the range from 10Ω to 0.01Ω, 0.025% in the range from 0.1Ω to 0.01Ω

Resistance resolution

77μΩ @ 4A to1.5 μΩ @ 4A

Output current intensity

1 milliamp – 8000 milliamp

Output voltage

120 volts (optional 240 volt upgrade)

Input channels

180 base simultaneous receiver channels (not multiplexed)


Expandable multiplexing in groups of 60 sensors

Input gain ranging

Automatic or Manual

Input impedance

>10 M Ohm.


0.05 to 5 Hz

Duty Cycle

10 to 90 percent

Pulses per Measurement

Programmable from 1 to 1,000.

Measurement Time

Simultaneous 180 Channel Pole-Pole measurement sequence in ~15 minutes

Array Type

Measured pole-pole, calculated any dipole-dipole, Wenner, or custom designed 4-pole combinations.

Sampling Window

Operator adjustable

Filters (Noise suppression)

Analog (hardware) 10 Hz low pass or 1 kHz low pass
Digital (software) user selectable

Fault / Alarm Detection

Detects AC power fail, user-selected disconnect (override), open circuit (wire) detection, over-temperature, under temperature, system start, system stop, overvoltage, trailer entry alarm, lightning proximity notification

Programmable email and text notifications


Modular design can be serviced with single Philips head screwdriver


Emergency stop in and outside, manual lockout to support lock-out & tag-out protocols

Error analysis

Point-to-Point error and Pulse-to-Pulse error

Powerline noise suppression

50 and 60 Hz (see filters)

Total accuracy

< 0.2% hardware with software calibration on NIST traceable calibration test box

System calibration

Externally calibrated using NIST traceable calibration box

Operating system

Windows 7

Data storage

Redundant enterprise-grade laptop hard drives

SQL Database storage

ASCII CSV summary files

Binary full-waveform files

Data display

Numeric and graphical, full waveform, web-based visualization software

Remote Control

Full control via remote login including system calibration

Data Processing

Automatic detection of anomalous voltage conditions indicative of leaks. Leak rate estimation. Leak potential indication.

Memory capacity

Limited to hard drive size

Data transmission

USB, Wireless Network (LAN), Internet, 2-way Satellite optional

Quality Assurance

NQA-1 since 2004

Electrical Safety

UL Listed/NEC compliant, plug and cord design for maintenance safety


System housed in a portable trailer equipped with climate controls, uninterruptable power supply, weather monitoring, and wireless communications


22 and 37 inch 1080p displays

Input Power

240V 50Amp

Operating temperature

Climate controlled trailer