Apparatus and method for determining borehole size with a borehole imaging tool

Patent metadata

Field	Value
Publication number	US-11815352-B2
Application number	US-202117217734-A
Country	US
Kind code	B2
Filing date	Mar 30, 2021
Priority date	Feb 17, 2015
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

A downhole borehole imaging tool and methods for determining a borehole size includes a magnetoresistive system and a hub moveably coupled to a fixed tool string. The hub includes a magnet. The magnetoresistive system includes magnetoresistive sensors disposed within the fixed tool string and segregated from the magnet. During operation, a routine scan of all sensors measures, for example, the output voltage V, angle θ of magnetic field, and temperature. Measurements from each sensor may then be characterized to account for temperature and input voltages variation of the sensors. The most accurate measurement can be used to derive the position of the hub 44 using the previous baseline parameters stored in the tool.

First claim

What is claimed is:

1. A logging tool, comprising:
a tool string having a longitudinal axis;
a plurality of springs comprising first and second pairs of springs coupled to the tool string, wherein the springs of the first pair are disposed opposite one another about the longitudinal axis, a first end of each spring of the plurality of springs is rigidly fixed to the tool string to block both axial motion of the first end along the longitudinal axis and rotational motion of the first end about the longitudinal axis, the first end of each spring of the first pair of springs is disposed at a first axial position along the tool string, the first end of each spring of the second pair of springs is disposed at a second axial position along the tool string, and the first and second axial positions are different from one another;
a plurality of sensors, wherein one sensor of the plurality of sensors is disposed on one spring of the first pair of springs, and another sensor of the plurality of sensors is disposed on one spring of the second pair of springs;
a first hub connected to a second end of each spring of the first pair of springs, wherein the first hub is disposed about and moveably coupled to the tool string, and wherein the first hub comprises a first magnet having a first magnetic field; and
an array of magnetoresistive sensors disposed in the tool string such that the first hub is configured to move along the longitudinal axis of the tool string about the array of magnetoresistive sensors.

2. The logging tool of claim 1 , wherein the logging tool is configured to be stored within a drill string extending into a borehole, and wherein the logging tool is configured to extend through a drill bit disposed on an end of the drill string.

3. The logging tool of claim 2 , wherein the logging tool is configured to make borehole measurements while the drill string is being removed from the borehole.

4. The logging tool of claim 1 , wherein the first magnetic field of the first magnet is configured to interact with the array of magnetoresistive sensors as the first hub moves along the longitudinal axis of the tool string about the array of magnetoresistive sensors.

5. The logging tool of claim 1 , wherein at least one sensor of the plurality of sensors is configured to measure a property of a formation when the logging tool is disposed within a borehole located within the formation.

6. The logging tool of claim 5 , wherein the logging tool is configured to press the at least one sensor against a sidewall of the borehole to measure the property of the formation when the logging tool is disposed within the borehole.

7. The logging tool of claim 5 , wherein the at least one sensor is a non-contact sensor configured to remain out of contact with a sidewall of the borehole when the property of the formation is measured.

8. The logging tool of claim 1 , wherein disposing the array of magnetoresistive sensors in the tool string causes the array of magnetoresistive sensors to be at a pressure substantially equal to atmospheric pressure when the logging tool is disposed within a borehole.

9. The logging tool of claim 1 , wherein an inner surface of a bore defined by the first hub that is disposed about the tool string and an outer surface of the tool string are separated by a gap and directly opposed to one another.

10. The logging tool of claim 9 , wherein an outer cross-sectional shape of the tool string the hub is disposed about and moveably coupled to includes a corner.

11. The logging tool of claim 1 , wherein an outer cross-sectional shape of the tool string the first hub is disposed about and moveably coupled to includes a corner.

12. The logging tool of claim 11 , wherein:
the logging tool is configured to be stored within a drill string extending into a borehole located within a formation, and
the logging tool is configured to extend through a drill bit disposed on an end of the drill string and into the borehole.

13. The logging tool of claim 12 , wherein the logging tool is configured to make borehole measurements while the drill sting is being removed from the borehole.

14. The logging tool of claim 13 , wherein:
at least one sensor of the plurality of sensors is configured to measure a property of a formation when the logging tool is disposed within the borehole, and
the at least one sensor is a non-contact sensor configured to remain out of contact with a sidewall of the borehole when the property of the formation is measured,
wherein disposing the array of magnetoresistive sensors in the tool string causes the array of magnetoresistive sensors to be at a pressure substantially equal to atmospheric pressure when the logging tool is disposed within the borehole.

15. The logging tool of claim 1 , wherein the springs of the second pair are disposed opposite one another about the longitudinal axis.

16. The logging tool of claim 1 , wherein the plurality of springs are circumferentially offset from one another about the longitudinal axis.

17. The logging tool of claim 16 , wherein the first ends of the first pair of springs are disposed axially between the first and second ends of the second pair of springs, and the second ends of the second pair of springs are disposed axially between the first and second ends of the first pair of springs.

18. The logging tool of claim 17 , wherein:
the one sensor of the plurality of sensors is disposed on the one spring of the first pair of springs between the first and second ends of the one spring of the first pair of springs; and
the another sensor of the plurality of sensors is disposed on the one spring of the second pair of springs between the first and second ends of the one spring of the second pair of springs.

19. The logging tool of claim 1 , comprising a second hub connected to the second end of each spring of the second pair of springs, wherein the second hub is disposed about and moveably coupled to the tool string.

20. The logging tool of claim 19 , wherein the second hub comprises a second magnet having a second magnetic field, and the second hub is configured to move along the longitudinal axis of the tool string about the array of magnetoresistive sensors.

Assignees

• Schlumberger Technology Corp

Inventors

• Toniolo Julien
• Sallwasser Alan J
• Wells Peter
• Fredette Mark A

Classifications

• G01B7/13 Primary

  Internal diameters · CPC title

• E21B47/0025

  generating an image of the borehole wall using down-hole measurements, e.g. acoustic or electric · CPC title

• G01V3/26

  operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device (with electromagnetic waves G01V3/30) · CPC title

• G01V3/38

  Processing data, e.g. for analysis, for interpretation, for correction · CPC title

• E21B47/08 Primary

  Measuring diameters or related dimensions at the borehole · CPC title