SAMPLE HOLDER FOR USE IN NMR

• US 20130335081A1
• Filed: 06/18/2013
• Published: 12/19/2013
• Est. Priority Date: 06/19/2012
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: FORDHAM, EDMUND J.
• Granted Patent: US 10,209,324 B2
• Time in Patent Office: Days
• US Class Current: 324/309
• CPC Class Codes: G01N 24/081 Making measurements of geologic samples, e.g. measurements of moisture, pH, porosity, permeability, tortuosity or viscosity
• CPC Class Codes: G01R 33/305 specially adapted for high-pressure applications

Abstract

A pressurizable holder for a sample to be examined by NMR, comprises a pressure retaining nonmagnetic tube surrounding a radio-frequency coil which in turn surrounds a space for the sample. The pressure retaining tube is formed of (i) nonmetallic electrically insulating material such as a ceramic or (ii) nonmetallic electrically insulating matrix material reinforced with electrically insulating filaments such as glass fiber, or (iii) non-metallic electrically insulating matrix material reinforced with electrically conductive filaments configured so that conductivity is anisotropic. There is good coil filling factor without constraint on wall thickness of the pressure retaining tube. Avoidance of isotropically conductive material inhibits eddy currents when an NMR spectrometer'"'"'s magnetic field gradient coils are switched on and off. The tube resists hoop stress from internal pressure. Longitudinal stress is resisted by structure connecting end pieces at the ends of the pressure retaining tube.

Claims

1. A pressurizable holder for a sample to be examined by NMR, comprising a pressure retaining nonmagnetic tube formed of nonmetallic electrically insulating material or non-metallic electrically insulating matrix material reinforced with electrically conductive filaments configured to have less conductivity transverse to the filaments than along the filaments so as in either case to inhibit induced eddy currents, wherein the tube surrounds at least one radio-frequency coil and the at least one radio-frequency coil surrounds a space for the sample.

2. The sample holder of claim 1, wherein the pressure retaining tube is formed of electrically insulating material comprising non-metallic electrically insulating matrix material reinforced with non-metallic electrically insulating reinforcing filaments.

3. The sample holder of claim 1, wherein the pressure retaining tube is formed of a non-metallic composite material comprising electrically insulating matrix material reinforced with carbon fibers.

4. The sample holder of claim 1, wherein the pressure retaining tube is formed of a non-metallic composite material comprising electrically insulating matrix material reinforced with both carbon fibers and electrically insulating fibers.

5. The sample holder of claim 1, wherein the matrix material is an organic polymer.

6. The sample holder of claim 1, further comprising pieces to apply force longitudinally at the ends of the pressure retaining tube and connecting structure extending between these pieces outside the pressure retaining tube.

7. The sample holder of claim 6, wherein the connecting structure lies within a circular cross section which is not more than twice the diameter of the pressure retaining tube.

8. The sample holder of claim 1, wherein the at least one radio-frequency coil surrounds an electrically insulating tube to contain a liquid sample.

9. The sample holder of claim 8, wherein a pressurizable space between the pressure retaining tube and the electrically insulating tube for the liquid sample contains the at least one radio-frequency coil.

10. The sample holder of claim 8, wherein the electrically insulating tube for the liquid sample contains a movable piston to separate the sample from a pressure-controlling liquid maintained under pressure as the sample enters the tube at a higher pressure.

11. The sample holder of claim 10, wherein a pressurizable space between the pressure retaining tube and the electrically insulating tube for the liquid sample contains the at least one radio-frequency coil and is configured to be in pressure communication with the pressure controlling liquid.

17. An NMR spectrometer providing a magnetic field and having a sample holder as claimed in claim 1, placed in the magnetic field such that the axis of the pressure retaining tube is transverse to the magnetic field and having the at least one radio-frequency coil of the sample holder connected to the spectrometer, so that application of a radio-frequency signal to a coil by the spectrometer induces magnetic resonance of nuclei in a sample within the sample holder.

18. A method of examining a sample by NMR comprising placing a sample in a sample holder as claimed in claim 1, placing the sample holder in an NMR spectrometer such that the axis of the pressure retaining tube is transverse to the magnetic field, connecting the at least one radio-frequency coil of the sample holder to the spectrometer, applying a radio-frequency signal to the at least one radio-frequency coil to induce magnetic resonance of nuclei in the sample, and using the at least one radio-frequency coil to receive radio-frequency emissions from the sample.

19. An NMR spectrometer providing a magnetic field and having a sample holder as claimed in claim 8, placed in the magnetic field such that the axis of the pressure retaining tube is transverse to the magnetic field and having the at least one radio-frequency coil of the sample holder connected to the spectrometer, so that application of a radio-frequency signal to a coil by the spectrometer induces magnetic resonance of nuclei in a sample within the sample holder.

20. A method of examining a sample by NMR comprising placing a sample in a sample holder as claimed in claim 8, placing the sample holder in an NMR spectrometer such that the axis of the pressure retaining tube is transverse to the magnetic field, connecting the at least one radio-frequency coil of the sample holder to the spectrometer, applying a radio-frequency signal to the at least one radio-frequency coil to induce magnetic resonance of nuclei in the sample, and using the at least one radio-frequency coil to receive radio-frequency emissions from the sample.

12. A pressurizable holder for a liquid sample to be examined by NMR which comprises a pressure retaining tube surrounding at least one radio-frequency coil and the at least one radio-frequency coil surrounds an electrically insulating tube to contain the liquid sample.

13. The sample holder of claim 12, wherein the pressure retaining tube is formed of a non-metallic composite material comprising electrically insulating matrix material reinforced with both carbon fibers and electrically insulating fibers.

14. The sample holder of claim 12, wherein the space which contains the at least one radio-frequency coil between the pressure retaining tube and the electrically insulating tube for the liquid sample is configured to be pressurizable.

15. The sample holder of claim 12, wherein the tube for the liquid sample contains a movable piston to separate the sample from a pressure-controlling liquid maintained under pressure as the sample enters the tube at a higher pressure.

16. The sample holder of claim 15, wherein the space between the pressure retaining tube and the electrically insulating tube for the liquid sample is configured to be in pressure communication with the pressure controlling liquid.