Systems and methods for detecting a neutron generator operating in air

Patent metadata

Field	Value
Publication number	US-10852283-B2
Application number	US-201715841641-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 14, 2017
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A system that may identify when a pulsed neutron generator is operating while disposed in an undesirable environment, such as in air, may include a pulsed neutron generator designed to emit neutrons in an environment. The system may also include a radiation detector designed to take measurements of the neutrons. The system may also include data processing circuitry designed to determine if the environment surrounding the pulsed neutron generator is air based at least in part on a neutron signal obtained by the radiation detector. The determination may include comparing one or more characteristics of the neutron signal with corresponding reference characteristics.

First claim

The invention claimed is:

1. A system comprising:
a pulsed neutron generator configured to emit neutrons in an environment;
a radiation detector configured to take measurements of the neutrons; and
data processing circuitry configured to determine if the environment surrounding the pulsed neutron generator is an air environment, based at least in part on a neutron signal obtained by the radiation detector, wherein the determination comprises comparing one or more characteristics of the neutron signal with one or more corresponding reference characteristics, wherein the data processing circuitry is configured to deactivate the pulsed neutron generator in response to determining that the pulsed neutron generator is in the air environment.

2. The system of claim 1 , wherein the radiation detector is a neutron detector configured to detect thermal or epithermal neutrons.

3. The system of claim 1 , wherein the one or more corresponding reference characteristics are indicative of a reference environment.

4. The system of claim 1 , wherein the neutron signal is normalized to both the spectrum maximum and a reference time spectrum or a neutron emission count based at least in part on detections of a neutron monitor.

5. The system of claim 1 , wherein the neutron signal comprises a time spectrum.

6. The system of claim 5 , wherein the one or more characteristics of the neutron signal comprises a slope of a neutron count rate over the time spectrum.

7. The system of claim 6 , wherein the slope corresponds to the time spectrum of the neutron count rate during a neutron burst of the pulsed neutron generator.

8. The system of claim 5 , wherein the one or more characteristics of the neutron signal comprises an area defined at least in part by a curve of the time spectrum.

9. The system of claim 8 , wherein the area comprises an area under the curve of the time spectrum or an area between the curve of the time spectrum and a reference curve.

10. The system of claim 8 , wherein the area corresponds to the time spectrum during a neutron burst of the pulsed neutron generator.

11. The system of claim 5 , wherein the one or more characteristics of the neutron signal comprises a peak in the time spectrum.

12. The system of claim 5 , wherein the one or more characteristics are independent of a neutron flux of the neutron generator.

13. The system of claim 1 , wherein the one or more reference characteristics are threshold values.

14. The system of claim 1 , wherein the neutron signal comprises a ratio of a thermal neutron count and an epithermal neutron count.

15. A system comprising:
a pulsed neutron generator configured to emit neutrons in an environment;
a radiation detector configured to take measurements of the neutrons or neutron induced gamma rays; and
data processing circuitry configured to determine if the environment surrounding the pulsed neutron generator is an air environment, based at least in part on a time spectrum, wherein the time spectrum comprises a neutron or gamma ray count rate based at least in part on the measurements of the neutrons or gamma rays and to deactivate the pulsed neutron generator in response to determining that the pulsed neutron generator is in the air environment.

16. The system of claim 15 , wherein the radiation detector is configured to detect neutrons and gamma rays.

17. A method for deactivating a neutron generator in an undesired environment comprising:
emitting neutrons, from the neutron generator, into an environment;
detecting the neutrons or neutron induced gamma rays using one or more detectors;
determining, via a processor, from the detected neutrons or gamma rays a time spectrum;
determining, via the processor, if the environment is undesirable based at least in part on one or more characteristics of the time spectrum; and
in response to determining that the environment is undesirable, disabling, via the processor, the neutron generator.

18. The method of claim 17 , wherein the undesired environment is air.

19. The method of claim 17 , comprising evaluating a difference between the one or more characteristics and one or more reference characteristics using a statistical analysis.

Assignees

• Schlumberger Technology Corp

Inventors

• Mauborgne Marie-Laure
• Allioli Francoise
• Manclossi Mauro
• Nicoletti Luisa

Classifications

• G01N33/0073 Primary

  Control unit therefor · CPC title

• G01N33/0027

  concerning the detector · CPC title

• G01V5/102

  the neutron source being of the pulsed type · CPC title

• G01V5/108

  the neutron source being of the pulsed type · CPC title