Mount Sopris Instrument Company, together with Ontash & Ermac and Rutgers University, are developing a new borehole probe based on Spectral Induced Polarization (SIP) technology. This SIP probe is directly relevant for subsurface investigations in following fields:

  • Hydrogeology
  • Environmental
  • Mineral Exploration
  • COSequestration
  • Oil & gas
  • Geotechnical



The SIP method is one of the most robust and reliable methods for the indirect determination of lithological / physical properties of earth media such as:

  • Permeability/Hydraulic Conductivity
  • Effective Porosity
  • Grain/Pore Size & Distribution
  • Surface Area


Operating Conditions

Borehole Fluidsip-diagram
[X] Water
[X] Mud
[_] Dry

[X] Uncased
[_] PVC Borehole
[_] Steel

[_] Required
[X] Not Necessary


Features & Benefits

  • Can replace conventional resistivity logs as it provides a superset of measurements.
  • Offers some key advantages as a complementary logging technology for nuclear magnetic resonance (NMR) instruments and other borehole logging tools.
  • A promising “safe” alternative to nuclear logging tools that depend upon newly restricted radioactive material due to national security concerns.


Specifications – Metric/Imperial

Specification Metric Imperial
Diameter 50.8 mm 2″
Length 330.2 cm 130″
Max. Temp. 70ºC 158ºF
  • 4-electrode Wenner array configuration
  • 1mHz – 10kHz frequency range
  • Excitation Voltage: ±10.24V (20.48V p-p)
  • Excitation Current: 200mA
  • Differential Voltage Sense
  • Borehole temperature measurement
  • Wireline and Ethernet interfaces to surface


SIP Measurement Theory of Operation

The Spectral Induced Polarization response (also known as Complex Resistivity) is measured by applying sine wave currents in the frequency range between 1 mHz and 10 kHz. Impedance |Z| and phase ϕ are determined by correlating induced voltage U and stimulus current I.



Development Team


For over 60 years, Mount Sopris Instrumentmount_sopris_whites has delivered innovative borehole logging solutions to drillers, miners, engineers and researchers in over 120 countries. With an extensive product range and industry-leading customer support, Mount Sopris is dedicated pushing the boundaries of science to improve productivity and data integrity.


Advanced Logic Technology is a software and hardware development company bringing innovative solutions to the geoscience industry since 1993, including best-in-class log composite software, WellCAD, and industry-leading imaging probes.


ontashOntash & Ermac (O&E) is a leading developer and supplier of spectral induced polarization (SIP) equipment for use in laboratory, surface, and borehole applications. Since 1996, O&E has developed sophisticated electronics systems used in consumer, building systems, defense, medical, telecommunications and industrial automation systems.



rutgersLed by Dr. Lee Slater, Rutgers University has been a leader in innovative research on the SIP method since the late 1990’s. With hundreds of peer reviewed publications, Rutgers is on the forefront of advancing SIP understanding for hydrogeological and environmental problems.


nsfThe National Science Foundation (NSF) is funding the initial development work for the SIP probe. The NSF exists to support scientific research to create knowledge that transforms the future.



Product Roadmap

  • 2018 Q4: Design verification testing of probe in shallow borehole of known geophysical parameters
  • 2019 Q1: Integration with MSI surface equipment, including wireline communications
  • 2019 Q3: Testing of prototype in boreholes of known geophysical parameters and borehole conditions
  • 2020 Q1: Anticipated product release of commercial probe
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