NMR flow metering using velocity selection and remote detection

• US 8,633,689 B2
• Filed: 12/17/2010
• Issued: 01/21/2014
• Est. Priority Date: 10/19/2010
• Status: Active Grant

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Li, Lilong, Chen, Songhua, Edwards, Carl M.
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): MILLER, DANIEL R
• Application Number:
  US12/971,740
• Publication Number:
  US 20120092007A1
• Time in Patent Office: 1,131 Days
• Field of Search: 324300-322, 600407-435, 382128-131
• US Class Current: 324/306
• CPC Class Codes: G01F 1/716 using electron paramagnetic resonance [EPR] or nuclear magnetic resonance [NMR]
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• 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: G01N 24/082 Measurement of solid, liquid or gas content
• CPC Class Codes: G01R 33/445 MR involving a non-standard magnetic field B0, e.g. of low magnitude as in the earth's magnetic field or in nanoTesla spectroscopy, comprising a polarizing magnetic field for pre-polarisation, B0 with a temporal variation of its magnitude or direction such as field cycling of B0 or rotation of the direction of B0, or spatially inhomogeneous B0 like in fringe-field MR or in stray-field imaging

Abstract

A method and apparatus for estimating a flow rate of a phase of a multiphase fluid is disclosed. In the first method, nuclei in the fluid are polarized over two distances and a measured magnetization gives the relative fraction of two components of the fluid for a selected velocity. In the second method, nuclei in the fluid are polarized over a specified distance and measurements of the decay of spin echo signals is used to give the relative fraction of two components of the fluid for the selected velocity.

Claims

1. A method of estimating a flow rate of a phase of a fluid having a plurality of components, the method comprising:

using a magnet for polarizing nuclei of the fluid flowing over a plurality of distances wherein a number of the distances is equal to or greater than a number of the components;

measuring a magnetization of the polarized nuclei for each of the plurality of distances for a selected flow velocity;

using the plurality of measured magnetizations for estimating a relative fraction of each of the plurality of components corresponding to the selected velocity;

wherein measuring the magnetization of the polarized nuclei further comprises pulsing a first coil with a tipping pulse, pulsing a second coil with a refocusing pulse, and measuring an echo resulting from the refocusing pulse with a third coil.

2. The method of claim 1 wherein a time interval between the tipping pulse and the refocusing pulse is a defined by the selected velocity and a distance between the first coil and the second coil.

3. The method of claim 1 wherein the fluid is flowing in a conduit inside the magnet.

4. The method of claim 1 wherein the fluid is flowing in an earth formation outside the magnet.

5. The method of claim 1 further comprising pulsing the first coil and the second coil at a Larmor frequency corresponding to nuclei of ¹H and ¹³C.

6. The method of claim 1 wherein the fluid contains the nuclei of ¹³C, the method further comprising enhancing the polarization of the nuclei of ¹³C using at least one of:

(i) electron spin resonance, (ii) a Nuclear Overhauser Effect, and (iii) optical pumping and Spin Induced Nuclear Overhauser Effect.

7. An apparatus configured to estimate a flow rate of a phase of a fluid having a plurality of components, the apparatus comprising:

a magnet configured to polarize nuclei of the fluid flowing over a plurality of distances wherein a number of the distances is equal to or greater than a number of the components;

a coil arrangement configured to measure a magnetization of the polarized nuclei for each of the plurality of distances for a selected flow velocity, wherein the coil arrangement further comprises a first coil configured to pulse the polarized nuclei with a tipping pulse, a second coil configured to pulse the polarizing nuclei with a refocusing pulse, and a third coil configured to measure an amplitude of an echo resulting from the refocusing pulse;

a processor configured to use the plurality of measured magnetizations to estimate a relative fraction of each of the plurality of components corresponding to the selected velocity.

8. The apparatus of claim 7 wherein a time interval between the tipping pulse and the refocusing pulse is a defined by the selected velocity and a distance between the first coil and the second coil.

9. The apparatus of claim 7 further comprising a conduit inside the magnet for conveying the fluid.

10. The apparatus of claim 9 wherein the conduit is selected from:

(i) production tubing in a hydrocarbon producing well, (ii) production tubing in a geothermal well, (iii) a drilling tubular conveying drilling fluid, and (iv) a riser in offshore drilling.

11. The apparatus of claim 7 wherein the fluid is flowing in an earth formation outside the magnet.

12. The apparatus of claim 7 further comprising pulsing the first coil and the second coil at a Larmor frequency corresponding to nuclei of ¹H and ¹³C.

13. The apparatus of claim 7 wherein the fluid contains nuclei of ¹³C, the apparatus further comprising a device for enhancing the polarization of nuclei of ¹³C in the fluid using at least one of:

(i) electron spin resonance, (ii) a Nuclear Overhauser Effect, and (iii) optical pumping and Spin Induced Nuclear Overhauser Effect.

14. A method of estimating a flow rate of a phase of a fluid having a plurality of components, the method comprising:

using a magnet for polarizing nuclei of the fluid flowing over a selected distance;

pulsing the polarized nuclei with a tipping pulse with a first coil, a refocusing pulse with a second coil at a first distance from the first coil, a refocusing pulse with a third coil at a second distance from the first coil, and measuring an echo signal for each of the plurality of distances for a selected flow velocity;

using the plurality of echo signals for estimating a relative fraction of each of the plurality of components corresponding to the selected velocity.

15. The method of claim 14 wherein a time interval between the tipping pulse and the refocusing pulse is defined by the selected velocity and a distance between the first coil and the second coil.

16. The method of claim 14 wherein the fluid is flowing in a conduit inside the magnet.

17. The method of claim 14 wherein the fluid is flowing in an earth formation outside the magnet.

18. The method of claim 14 further comprising pulsing the first coil and the second coil at a Larmor frequency corresponding to nuclei of ¹H and ¹³C.

19. The method of claim 14 wherein the fluid contains the nuclei of ¹³C, the method further comprising enhancing the polarization of the nuclei of ¹³C using at least one of:

(i) electron spin resonance, (ii) a Nuclear Overhauser Effect, and (iii) optical pumping and Spin Induced Nuclear Overhauser Effect.

20. An apparatus configured to estimate a flow rate of a phase of a fluid having a plurality of components, the apparatus comprising:

a magnet configured to polarize nuclei of the fluid flowing over a selected distance;

a first coil arrangement configured to pulse the polarized nuclei with a tipping pulse, a second coil at a first distance from the first coil configured to pulse the polarized nuclei with a refocusing pulse, the third coil at a second distance from the first coil configured to pulse the polarized nuclei with a refocusing pulse, and at least one additional coil configured to measure and echo signal for each of the plurality of distances for a selected flow velocity; and

a processor configured to use the plurality of echo signals to estimate a relative fraction of each of the plurality of components corresponding to the selected velocity.

21. The apparatus of claim 20 wherein a time interval between the tipping pulse and the refocusing pulse is a defined by the selected velocity and a distance between the first coil and the second coil.

22. The apparatus of claim 20 wherein the fluid is flowing in a conduit inside the magnet.

23. The apparatus of claim 22 wherein the conduit is selected from:

(i) production tubing in a hydrocarbon producing well, (ii) production tubing in a geothermal well, (iii) a drilling tubular conveying drilling fluid, and (iv) a riser in offshore drilling.

24. The apparatus of claim 20 wherein the fluid is flowing in an earth formation outside the magnet.

25. The apparatus of claim 20 further comprising pulsing the first coil and the second coil at a Larmor frequency corresponding to nuclei of ¹H and ¹³C.

26. The apparatus of claim 20 wherein the fluid contains nuclei of ¹³C , the apparatus further comprising a device for enhancing the polarization of nuclei of ¹³C in the fluid using at least one of:

(i) electron spin resonance, (ii) a Nuclear Overhauser Effect, and (iii) optical pumping and Spin Induced Nuclear Overhauser Effect.