Constrained backscatter gamma ray casing and cement inspection tool

Patent metadata

Field	Value
Publication number	US-10185052-B2
Application number	US-201615383978-A
Country	US
Kind code	B2
Filing date	Dec 19, 2016
Priority date	Dec 19, 2016
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

Methods, systems, devices, and products for estimating at least one parameter of interest of a volume of interest of an earth formation using nuclear radiation based measurements. Logging tools include a limited aperture collimated radiation beam source, detectors, and at least one processor configured to take measurements. The source is configured to emit a beam of radiation radially from the logging tool into an elongated volume of interest outside the wellbore such that the beam penetrates a plurality of zones of the volume of interest. Each zone represents a range of radial depths corresponding to a respective infrastructure component associated with the wellbore, such as nested tubulars. Each detector has a unique angle of detection and is configured to generate measurement information in response to spatially coherent backscattered gamma rays. Each detector is associated with scattering events at one of the plurality of zones.

First claim

What is claimed is:

1. A well logging apparatus comprising:
a logging tool for conveyance in a wellbore on a carrier comprising:
a radially oriented limited aperture collimated radiation beam source configured to emit, while in the wellbore, a beam of radiation radially from the logging tool into an elongated volume of interest outside the wellbore such that the beam penetrates a plurality of zones of the volume of interest, wherein each zone of the plurality represents a range of radial depths corresponding to a respective infrastructure component associated with the wellbore;
a plurality of radiation detectors distributed about the perimeter of the source, wherein each detector of the plurality has a unique angle of detection, the plurality of radiation detectors configured to generate measurement information in response to spatially coherent backscattered gamma rays from the plurality of zones, wherein each detector of the plurality is associated with scattering events at one of the plurality of zones;
at least one processor configured to take well logging measurements with the logging tool including:
using the beam source to emit the beam;
generating measurement information at the plurality of detectors responsive to the emitted beam; and
estimating a property of the respective infrastructure component at at least one zone using the measurement information.

2. The apparatus of claim 1 wherein the source is at substantially the same borehole depth as the plurality of detectors.

3. The apparatus of claim 1 wherein the volume of interest comprises a plurality of nested tubulars in the wellbore, and the infrastructure component comprises a structural feature relating to at least one tubular of the plurality of nested tubulars.

4. The apparatus of claim 3 wherein at least one tubular of the nested tubulars comprises cement adjacent to casing.

5. The apparatus of claim 3 wherein the property of the respective infrastructure component comprises at least one property of a defect of the component.

6. The apparatus of claim 1 wherein the processor is further configured to identify an anomaly in the infrastructure by detecting attenuated backscatter at a detector correlated with a corresponding zone.

7. The apparatus of claim 1 comprising a carrier, wherein the carrier comprises at least one of i) a drill string; and ii) a wireline.

8. The apparatus of claim 1 wherein the source is within 5 centimeters of axial spacing of the plurality of detectors.

9. A method of well logging using a logging tool in a wellbore in an earth formation, the method comprising:
conveying the logging tool in the wellbore on a carrier;
taking well logging measurements with the logging tool including:
emitting a beam of radiation having high spatial coherency from a source radially from the logging tool into a collimated volume of interest outside the wellbore such that the beam penetrates a plurality of zones of the volume of interest, wherein each zone of the plurality represents a range of radial depths corresponding to a respective infrastructure component associated with the wellbore;
generating measurement information at a plurality of detectors distributed about the perimeter of the source on the logging tool in response to spatially coherent backscattered gamma rays from the plurality of zones, wherein each detector of the plurality is associated with scattering events at one of the plurality of zones; and

estimating a property of the respective infrastructure component at at least one zone using the measurement information.

10. The method of claim 9 wherein the volume of interest comprises a plurality of nested tubulars in the wellbore, and the infrastructure component comprises a structural feature relating to at least one tubular of the plurality of nested tubulars.

11. The method of claim 10 wherein at least one tubular of the nested tubulars comprises cement adjacent to casing.

12. The method of claim 11 wherein the property of the respective infrastructure component comprises at least one property of a defect of the component.

13. The method of claim 9 further comprising:
estimating the property of the respective infrastructure component at a zone by using measurement information from another zone closer to a longitudinal axis of the tool than the zone to mitigate effects on measurement information from the zone comprising correcting for an influence of the other zone on the beam.

14. The method of claim 13 comprising performing an inversion on measurement information for at least the zone and the other zone.

15. The method of claim 9 comprising performing an inversion on measurement information for the at least one zone at a plurality of wellbore depths.

16. The method of claim 9 wherein each detector is configured with an angle of detection aligned with a corresponding zone of the plurality of zones.

17. The method of claim 16 further comprising:
identifying an anomaly in the infrastructure by detecting attenuated backscatter at a detector correlated with a corresponding zone.

18. The method of claim 9 comprising:
modeling a predicted signal response for each detector corresponding to at least one anomaly; and
comparing the information with the predicted signal response to identify the anomaly.

19. The method of claim 9 comprising wherein the carrier comprises at least one of i) a drill string; and ii) a wireline.

20. The method of claim 9 comprising conducting further operations in dependence upon the property.

21. The method of claim 20 wherein the further operations comprise at least one of: i) geosteering; ii) drilling additional wellbores in the formation; iii) performing additional measurements on the formation; iv) estimating additional parameters of the formation; v) installing equipment in the wellbore; vi) repairing infrastructure; vii) optimizing present or future development in the formation or in a similar formation; viii) optimizing present or future exploration in the formation or in a similar formation; and ix) producing one or more hydrocarbons from the formation.

22. The method of claim 9 wherein estimating the property of the respective infrastructure component comprises:
performing a joint inversion using the measurement information and additional measurement information from an additional tool comprising at least one of:
i) an electromagnetic tool, and ii) an acoustic tool
to resolve a structural feature relating to at least one tubular of the plurality of nested conductive tubular, the structural feature comprising at least one of: i) tubular ovality of the at least one tubular; ii) deformation of the at least one tubular; iii) corrosion of the at least one tubular, iv) perforation of the at least one tubular, v) a presence of a completion component outside of the at least one tubular, vi) eccentricity of the at least one tubular with respect to another component, vii) a material property of the at least one tubular; and viii) a material property of a material surrounding the at least one tubular.

23. The method of claim 9 wherein estimating the property of the respective infrastructure component comprises:
performing a sequential inversion using the measurement information and additional measurement information from an additional tool comprising at least one of:
i) an electromagnetic tool, and ii) an acoustic tool
to resolve a structural feature relating to at least one tubular of the plurality of nested

Assignees

• Baker Hughes Inc
• Baker Hughes A Ge Co Llc

Inventors

• Inanc Feyzi
• Patterson Douglas
• Onegova Elizaveta
• Difoggio Rocco
• Fanini Otto

Classifications

• G01V5/12

  using gamma or X-ray sources {(gamma sources using isotopes G21G4/00; X-ray tubes H01J35/00)} · CPC title

• G01V5/045 Primary

  Transmitting data to recording or processing apparatus; Recording data · CPC title

• G01V5/125 Primary

  and detecting the secondary gamma- or X-rays in different places along the bore hole · CPC title