Oxford Instruments plc

- Model GeoSpec2+ - Core Analyser



GeoSpec is the industry standard NMR core analyser, with installations in almost every major oil producer and SCAL laboratory world-wide. Our partnership with Green Imaging Technologies guarantees complete hardware and software integration which makes it possible for any core analysis laboratory to obtain comprehensive NMR core analysis results without the need for an in-house NMR expert.

The GeoSpec range currently comprises instrument models operating at 2, 12 and 20MHz.

2MHz models are the industry standard for routine measurements of relaxation distributions, leading to prediction of basic petrophysical parameters such as porosity, free and bound fluid determinations and T2 cutoff. These instruments operate at 2MHz to reduce artefacts caused by ferromagnetic material in the samples and to mimic the operation of the NMR logging tools.

All 2MHz GeoSpec models are equipped with Q-Sense, our ground-breaking technology for improved signal-to-noise and ultra-short echo times. Both these features are essential for accurate measurements on tight rocks and shales.

2MHz GeoSpec models are available in three different magnet sizes to accommodate cores from 1/2” to 6” diameter.

Higher field (12 and 20MHz) GeoSpec models are available for situations where higher sensitivity is required (for example, very low porosity samples), and for special applications such as Magnetic Resonance Imaging (MRI). Maximum sample size is smaller than for the 2MHz models, with the 12MHz model able to accommodate samples up to 53mm (2”) diameter and the 20MHz model up to 26mm (1”).


Until recently, a high level of expertise and knowledge of the principles and practice of NMR has been needed to perform NMR core analysis. Consequently, NMR core analysis has been confined to a relatively small group of Special Core Analysis Laboratories. Now, a partnership between Oxford Instruments and Green Imaging Technologies brings new hardware and software, with improved performance, to enable any core analysis laboratory to generate the petrophysics values that the industry needs without the requirement that every dataset be analysed by an NMR expert.

Now, any core analysis laboratory can add NMR to the techniques they can offer, allowing:

Well Log Calibration and giving fast measurement of:

  • Total Porosity
  • Capillary Pressure
  • Pore Size Distribution
  • Gas/Water Content
  • Bulk Volume Irreducible (BVI)
  • Oil/Water Content
  • Free Fluid Index (FFI)
  • Pore throat distribution
  • Clay Bound Water (CBW)
  • Wettability
  • Permeability
  • Fluid Typing

With the addition of extra hardware and software options, the GeoSpec range is also capable of more advanced research applications,
By adding an accessory called Pulsed Field Gradients (pfg) to the NMR instrument, it becomes possible to carry out measurements dependent on the diffusion, flow, or distribution of the fluids within the core sample. This allows us to conduct measurements to investigate, for example, fluid typing and fluid distribution.

Patented software allows 2-dimensional data maps to be constructed to help with fluid typing, and other patented software generates spatially-dependent T2 distributions from “slices” along the core length. It is also possible to carry our capillary pressure measurements in about a quarter of the time taken by the traditional centrifuge capillary pressure measurement, and with many more points on the capillary pressure curve.

Nuclear Magnetic Resonance (NMR) is a valuable tool for both routine core analysis and SCAL. Most measurements are made at ambient temperature and pressure, but it is becoming increasingly important to carry out measurements at as close to reservoir conditions as possible.

The P5 Cell, unique to the GeoSpec range of NMR rock core analysers and available for 2 and 12MHz models, allows users to do this. Designed and built with a focus on usability and performance, the cell allows users to pressurize samples with up to 5,000 psi of confining pressure, at up to 100ºC.

GeoSpec core analysers provide cutting edge solutions for the core analyst.

Petroleum engineers constantly strive for a better understanding of their reservoirs, which requires extensive and reliable data. GeoSpec NMR core analysers provide measured and modeled data directly from the fluids in the rocks to complement other technologies and help solve the reservoir puzzle.

The GeoSpec range of instruments is the result of a successful long-term collaboration between Oxford Instruments and Green Imaging Technologies (GIT), the world leaders in hardware and software for NMR core analysis. First introduced in the mid-1990s, the GeoSpec now has well over 100 installations worldwide in oil companies, service companies and academia.

The GeoSpec includes instruments from 2MHz to 23MHz operating frequency, handling samples from ½ to 6 inches diameter, with integrated software and accessories to suit all users from routine core analysis to advanced petrophysics research.

Entry level GeoSpec systems come complete with LithoMetrix™ software which carries out routine measurements such as T1 and T2-based pore size distributions, porosity, and fluid mobility measurements such as Free Fluid Index (FFI), Bound Volume Irreducible (BVI) and Clay Bound Water (CBW).

Higher performance hardware incorporating pulsed field gradients is matched with greater software capability including measurement of hydrogen index, diffusion, and fluid typing by 2-D data mapping.

Top of the range GeoSpec systems include saturation profiles, spatially-resolved T2 distributions, and GIT’s patented capillary pressure (Pc) measurement package, GIT-CAP™. GIT-CAP allows users to obtain Pc measurements 5 times faster, while getting up to 10 times as many data points per scan, compared to traditional measurement techniques.

With the optional P5 Cell for overburden studies, users can perform analysis on 1” and 1.5” diameter samples at up to 5,000 psi of pressure and at temperatures to 100°C.

All GeoSpec systems include Oxford Instruments’ revolutionary Q-Sense signal enhancement technology, which provides industry-leading short echo spacings (essential for measurements on tight rocks and shales, which have a high proportion of small pores) while maintaining high signal to noise ratios (SNR). This unique combination allows measurements to be made up to four times faster, with echo spacings several times shorter, than in previous instruments. Q-Sense also allows successive measurements to be made on cores of varying salinity, without the need to retune the probe between samples.

  • High SNR lets you get more from your sample and collect better data in less time.
  • High sensitivity for measurements on low porosity rocks.
  • External probe power dissipation for reduced thermal effects and high duty cycles.
  • See tight pore networks – Q-Sense signal enhancement means seeing extremely small pores, down to 1 nanometer.
  • Fastest, most accurate and data rich capillary pressure measurement available (GIT-CAP).
  • 1D and 2D gradients open up advanced petrophysical studies. 3D gradients allow 3D imaging (MRI) of core samples.
  • 2MHz models for optimum well log calibration; 12MHz and 20MHz models for greater sensitivity with low porosity samples.
  • Sample size from ½” diameter to 6” diameter
  • Overburden studies up to 5000psi and 100C, using dedicated cell with multiple levels of safety features

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