Garnet scintillator compositions for downhole oil and gas explorations

Patent metadata

Field	Value
Publication number	US-11994646-B2
Application number	US-202117199989-A
Country	US
Kind code	B2
Filing date	Mar 12, 2021
Priority date	Mar 12, 2021
Publication date	May 28, 2024
Grant date	May 28, 2024

Abstract

The use of scintillator compositions having a cubic garnet structure for gamma detection in downhole oil and gas explorations is provided. Specifically, two primary compositions of interest are disclosed, Ca 2 LnHf 2 Al 3 O 12 and NaLn 2 Hf 2 Al 3 O 12 , where Ln is Y, Gd, Tb, or La. Under gamma ray excitation, the electron-hole pairs produced in the garnet lattice structure are trapped by an activator ion to yield an efficient emission in the visible portion of the electromagnetic spectrum. The cubic garnet structure enables the use of these materials as ceramic scintillators with considerable advantages over related single crystals in various ways as disclosed herein, including reduction in cost and improvement in overall performance and durability.

First claim

What is claimed is:

1. A system for detecting gamma radiation in a downhole environment, the system comprising:
a detector positioned in a wellbore extending into a formation;
a scintillator positioned inside the detector which absorbs the gamma radiation and emits light based on an amount of the gamma radiation present, the scintillator having a cubic garnet structure and being formed from a grinding, a hot isostatic pressing, and a sintering process, the sintering process following the hot isostatic pressing, in which a ceramic powder with a particle size of 1-10 microns is used in the hot isostatic pressing, wherein the scintillator is comprised of NaLn 2 Hf 2 Al 3 O 12 and Ln is one of Y, Gd, Tb, or La;
a photomultiplier tube coupled to the scintillator for amplifying the emitted light; and
a measuring device coupled to the photomultiplier tube for measuring an amount of electrons in the emitted light.

2. The system of claim 1 , wherein the scintillator is a transparent ceramic.

3. A method for detecting gamma radiation in a downhole environment, the method comprising:
grinding a ceramic powder to a particle size of 1-10 microns;
hot isostatic pressing the powder into a solid ceramic;
sintering the solid ceramic;
forming a scintillation detector, comprising a scintillator including the solid ceramic, the solid ceramic being transparent and having a cubic garnet structure;
positioning the scintillation detector in a wellbore extending into a formation;
causing an interaction between the scintillator and the gamma radiation;
amplifying photons of light emitted from the scintillator responsive to the interaction between the scintillator and the gamma radiation; and
measuring an amount of photons in the emitted light from the scintillator.

4. The method according to claim 3 , wherein the scintillator is comprised of NaLn 2 Hf 2 Al 3 O 12 and Ln is one of Y, Gd, Tb, or La.

5. The method according to claim 3 , wherein the scintillator is comprised of Ca 2 LnHf 2 Al 3 O 12 and Ln is one of Y, Gd, Tb, or La.

6. A method for producing a scintillator for detecting gamma radiation in a downhole environment, the method comprising:
grinding a ceramic powder to a particle size of 1-10 microns;
hot isostatic pressing the powder into a solid ceramic; and
sintering the solid ceramic.

7. The method according to claim 6 , wherein the scintillator is comprised of NaLn 2 Hf 2 Al 3 O 12 and Ln is one of Y, Gd, Tb, or La.

8. The method according to claim 6 , wherein the scintillator is comprised of Ca 2 LnHf 2 Al 3 O 12 and Ln is one of Y, Gd, Tb, or La.

9. The method according to claim 6 , wherein the solid ceramic is transparent and has a cubic garnet structure.

10. A system for detecting gamma radiation in a downhole environment, the system comprising:
a detector positioned in a wellbore extending into a formation;
a scintillator positioned inside the detector which absorbs the gamma radiation and emits light based on an amount of the gamma radiation present, the scintillator having a cubic garnet structure and being formed from a grinding, a hot isostatic pressing, and a sintering process, the sintering process following the hot isostatic pressing, in which a ceramic powder with a particle size of 1-10 microns is used in the hot isostatic pressing, wherein the scintillator is comprised of Ca 2 LnHf 2 Al 3 O 12 and Ln is one of Y, Gd, Tb, or La;
a photomultiplier tube coupled to the scintillator for amplifying the emitted light; and
a measuring device coupled to the photomultiplier tube for measuring an amount of electrons in the emitted light.

11. The system of claim 10 , wherein the scintillator is a transparent ceramic.

Assignees

• Baker Hughes Oilfield Operations Llc

Inventors

• Srivastava Alok M
• Climent Helene Claire
• Comanzo Holly A

Classifications

• G01T1/1645

  using electron optical imaging means, e.g. image intensifier tubes, coordinate photomultiplier tubes, image converter · CPC title

• G01T1/2026

  Well-type detectors · CPC title

• G01T1/2023

  Selection of materials · CPC title

• G01T1/2006

  using a combination of a scintillator and photodetector which measures the means radiation intensity · CPC title

• G01V5/06 Primary

  for detecting naturally radioactive minerals · CPC title