Magnetic Resonance Borehole Logging Tools

High-Resolution Downhole Measurement and Characterization of Aquifer Properties

Vista Clara’s advanced Javelin family of borehole NMR magnetic resonance logging tools provide direct, low-cost, high-resolution measurements of hydrogeological properties that users really care about, including:

  • Volumetric water content
  • Pore size distribution
  • Bound and mobile aquifer porosity
  • Hydraulic conductivity
  • Transmissivity

A single Javelin NMR log can provide all of these key hydrogeological properties at vertical resolution on the order of 25 to 50 centimeters, enabling unambiguous and precise characterization of the water storage and pore structure characteristics of any earth formations.

Javelin NMR logging adds incredible value to any open hole or PVC-cased hole subsurface investigation, especially when compared to the cost of drilling and the costs and limitations of other methods for measuring aquifer properties.  

All of the Javelin family products described below are available globally for purchase or rental, along with comprehensive professional support services to help our customers get the most value from their investments in Javelin borehole logging equipment.

Javelin Wireline Slim

For Professional Geophysical Logging Operators

Javelin Wireline Slim is the newest and most advanced member of the family (introduced in 2019). It features state-of-the-art electronics housed in a 2.38 inch diameter Power & Digital Module, which can be used with two interchangeable lower probe modules with diameters of 2.38 inches or 3.5 inches.

This flexibility makes it well-suited for small to medium diameter core holes and groundwater wells, ranging from 3 to 12 inches.

Javelin Wireline Slim key capabilities include:

  • Two simultaneous diameters of investigation (2-frequency operation)
  • Interchangeable lower probe sections (2.38 or 3.50 inches diameter)
  • Simplified, compact downhole electronics
  • Wide diameter, high-resolution logging capabilities
  • Can be used to log PVC-cased wells or open holes

For More Info:
Download Javelin Slim Specifications

Javelin Wireline Max

For Medium and Large Diameter Groundwater Wells

Javelin Wireline offers large-diameter, three-frequency logging with interchangeable 3.5-inch and 5.25-inch sensors.

Javelin Wireline Max key capabilities include:

  • Well-suited for logging medium to large groundwater wells from 5 inches to 20 inches in diameter
  • Up to 3 simultaneous diameters of investigation (3-frequency operation)
  • 525 probe can log very large diameter production wells

For More Info:
Download Javelin Max Specifications


Portable Go-Anywhere Magnetic Resonance Logging Solution

Dart packs the power of magnetic resonance logging into a highly portable, battery-powered system operable by a single user. With Dart, any small-diameter bore—no matter how remote—becomes an opportunity for a high-resolution hydrogeologic log.

Dart is the world’s first and only hand-portable NMR logging tool, enabling single-person manual deployment to remote or environmentally sensitive locations, and eliminating the need for a multi-person crew or vehicle. Dart runs on batteries that last up to a full day of logging. A single user can transport and operate a Dart system, even in rough or challenging terrain.

Dart NMR Control Unit:

This rugged and highly portable product functions as a complete, field capable NMR spectrometer. The Dart control unit provides power, wideband RF power amplification, NMR pulse sequence generation and synchronous low-noise NMR signal data acquisition, all in one environmentally-sealed enclosure. This unit interfaces with a Windows field tablet or laptop via a single USB connection, enabling NMR measurements to be acquired and analyzed in real time in the field.

Dart NMR Logging Probe:

The Dart NMR logging probe features high performance NMR measurement capabilities, making it ideal for measuring water content in near surface soils and sediments:

  • A very short echo spacing (< 500 us) for the most accurate measurement of water content in unsaturated soils and sediments,
  • High vertical resolution (~9 inches/23 cm) for high resolution site characterization
  • Simultaneous measurement in two separate cylindrical sensitive zones with diameters of 5 inches (12.5 cm) and 6 inches (15 cm). These sensitive zone diameters are ideal for logging small diameter core holes, auger holes, or 2 inch (50mm) PVC-cased wells installed by direct push or small diameter sonic drilling
  • Dart operates at frequencies between 420 kHz and 480 kHz, avoiding large radio frequency interference in the worldwide AM broadcast band (530 – 1610 kHz)

Dart Applications:

  • Environmental Site Characterization
  • Environmental Monitoring
  • Mining
  • Geotechnical
  • Shallow Groundwater Resources

A number of the features included in Dart are patented as follows:: US 10,302,733, 10,113,982 B2; US 10,162,026 B2; US 10,302,733 B2; US 9,348,054 B2; US 9,588,068 B2US 8,816,684 B2; US 8,736,264 B2
* Available with advanced diffusion measurement software for characterization of hydrocarbon contaminants

For More Info:
Download Dart Specifications Sheet

Advantages of Vista Clara Borehole Logging Tools

Javelin Value Summary

We understand that boreholes and water wells are constructed in a very wide range of diameters and depths, and using different drilling and well completion methods for their intended purposes. We also understand that different users have different market-driven and logistical requirements that impact their ability to use geophysical NMR logging tools on their projects.

Thus Vista Clara makes its Javelin NMR logging tools available in three different system configurations, to enable efficient and economical NMR logging across a the widest ranges of borehole sizes and depths, well construction methods, and user needs.

View Beyond Drilling Disturbance

It is crucial during NMR logging that the region of investigation is entirely within the undisturbed native formation. Javelin logging tools are uniquely designed and tuned specifically for groundwater and environmental wells where annular drilling disturbances, including mud invasion, are large compared to typical oil or gas wells. Every Javelin tool provides the largest available sensitive zone diameter for its size, ensuring the greatest possible confidence in your NMR data integrity.

Multi-Diameter Logging

Javelin acquires data at multiple frequencies during a single logging run to obtain sensitivity at up to three discrete diameters of investigation. Shells can be combined in post-processing to improve data quality or can be analyzed independently to assess radial variation or drilling artefacts.

In contrast to Javelin multi-frequency NMR logging, single-frequency NMR logging tools measure only in a single measurement shell at one fixed diameter of investigation. If you wanted to get the same high-value diversity of data from a single-frequency tool, you would need to carry several single-frequency NMR logging tools and log the same well multiple times with those several different tools!

Extended Pre-polarization Magnets for High-Speed Logging

All Javelin NMR logging probes have extended pre-polarization magnets located above and below the main detection coil. This enables pre-polarization of the NMR sensitive zone while the tool is moving, and enables accurate high-speed low-resolution NMR logging of bound and mobile water content, at speeds on the order of 1000 m/hr. This high-speed low-resolution logging capability is useful for acquiring a fast reconnaissance log of a deep well on an initial logging pass, prior to acquiring a high-resolution NMR log in sections of most interest.

Low-frequency operation

Javelin systems transmit and receive between 250kHz and 480kHz, which is below the worldwide AM radio broadcast band. Other NMR tools that operate in the AM band are susceptible to interference which can make measurements impossible. This lower-frequency operation has the additional benefit of making the Javelin less susceptible to perturbations from highly magnetic geology than higher-frequency NMR tools.

Widest Variety of Interchangeable Tool Sizes

  • Javelin’s NMR logging tools are offered in a wide range of diameters: 1.40, 1.75, 2.38, 3.0 3.5 and 5.25 inches
  • Javelin probes can be used to log PVC-cased wells or open holes
  • Individual Javelin downhole probes are interchangeable and inexpensive compared to other NMR logging tools, allowing operators to field a range of tools sizes

The Javelin Wireline NMR logging tools feature oil-field quality tool joints to enable quick, convenient and highly reliable interchanging of downhole probes in the field and at the wellsite.

Unique Capability to log 2 inch PVC-Cased Wells

Javelin® and Dart are the only NMR logging tools available anywhere than can log 2 inch PVC-cased wells. These 1.75 inch diameter tools provide sensitive zone diameters as large as 10 inches, allowing measurements past the drilling-disturbed annular space which is often mandated by regulation to be 7 to 8 inches.

Unique Direct Push Compatibility

Javelin are the only NMR logging tools that can be deployed via direct push technology.

Deployment of Vista Clara Javelin and Dart tools in a Direct Push process provides rapid NMR logging results without the cost and hassles of pre-drilling boreholes in each situation.

Geoprobe Direct Push Drilling Machine

Key advantages of direct push measurements also include:

  • Ability to acquire downhole data with high efficiency and minimal footprint (small rig)
  • Minimized environmental disturbance:
  • No generation of drill cutting (which may be contaminated)
  • No need to install permanent well (which could be a long-term liability)
  • Very high quality NMR data because there is not disturbance from an oversized bit

Direct Push combined with the unique value of Vista Clara NMR measurement adds significant value above what can be achieved using other direct push tools, including:

  1. Direct measurement of total volumetric water content (or porosity if saturated)
  2. Estimation of mobile, capillary and clay bound water content. Mobile water content directly correlates to effective porosity
  3. Estimation of hydraulic conductivity over a range of 5-6 orders of magnitude, with maximum range up to 1000 m/day
  4. Measurement of all of the properties above at a resolution of 9 inches (25 cm)
  5. Vertical resolution of <4inches (<10cm)
  6. Deployment through Geoprobe’s standard 2.25 inch (57mm) direct push tooling.


                                                        Actual NMR data collected using new 1.4” diameter Javelin direct push NMR logging tool.


Complete, User-Friendly Software

All Javelin NMR logging products come complete with all the software the user needs to be able to acquire their NMR logging data and process, display and fully interpret the NMR logging data in real time, in the field, where it counts most. Javelin software interfaces are intuitive and easy to use, and provide all the NMR processing and interpretation capabilities required.

List of NMR data outputs:

  • Interactive comparison and combination of multi-frequency data
  • Continuous T2 distribution (relative water filled pore size distribution)
  • Total volumetric water content (porosity if saturated)
  • Mobile, capillary bound and clay bound water fractions
  • Hydraulic Conductivity using built-in empirical models and user-defined local or formation-based calibration models
  • Intuitive Quality Control features and measures including noise level and quality factor tracking
  • Export data in multiple formats including native WellCad format

Customer-Centered Business Models

Vista Clara strives to make our Javelin products available to all customers via the business model that best suits their organizational and financing needs. We offer direct sale of all our products, with world-famous customer service. We also offer Javelin NMR logging products through weekly and monthly rentals, worldwide, at competitive rates. Finally, Vista Clara offers a range of support services to customers who prefer to utilize our extensive in-house expertise, including on-site training, remote data review and consulting, and assistance with NMR logging data collection itself. 

A number of the features in Vista Clara’s Javelin family are protected by US patents: US 10,113,982 B2; US 10,162,026 B2; US 10,302,733 B2; US 8,736,264; US 8,816,684 B2; US 9,348,054 B2; US 9.588,068 B2;

For a list of other resources: visit our Reference Library