Ferrofluid tool for enhancing magnetic fields in a wellbore

Patent metadata

Field	Value
Publication number	US-9797222-B2
Application number	US-201314422866-A
Country	US
Kind code	B2
Filing date	Dec 30, 2013
Priority date	Dec 30, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A tool for enhancing or directing magnetic fields using ferrofluids in a downhole system is provided. The downhole system can include a tool body, a source of ferrofluid, and a positioning magnet. The positioning magnet can magnetically couple with the ferrofluid from the source for enhancing or directing a magnetic field through at least a portion of an annulus between the tool body and a wellbore formation.

First claim

What is claimed is:

1. A downhole system, comprising:
a tool body;
a sensor positioned in or connected with the tool body in a position for detecting changes in a magnetic field that extends through at least a portion of an annulus between the tool body and a wellbore formation;
a source of ferrofluid coupled with or in the tool body and positioned to introduce ferrofluid through the tool body into the portion of the annulus; and
a positioning magnet magnetically coupled with the ferrofluid introduced into the portion of the annulus through the tool body from the source and positioned to enhance or direct the magnetic field through at least the portion of the annulus so that the magnetic field differs in strength or direction in comparison to the magnetic field in the absence of the ferrofluid.

2. The downhole system of claim 1 , further comprising an antenna positioned to at least one of transmit or receive RF magnetic signals through the ferrofluid arranged in the annulus.

3. The downhole system of claim 1 , further comprising a static magnet positioned in the tool body, the static magnet comprising the positioning magnet or a second magnet provided in addition to the positioning magnet, wherein the ferrofluid is arranged adjacent to the static magnet such that a strength of a magnetic field from the static magnet is increased at a distance from the static magnet in comparison to a strength of the magnetic field from the static magnet at the distance in the absence of the ferrofluid being arranged adjacent to the static magnet.

4. The downhole system of claim 1 , wherein the positioning magnet is magnetically coupled with the ferrofluid for arranging the ferrofluid from the source to span between the tool body and the wellbore formation.

5. The downhole system of claim 1 , further comprising a nuclear magnetic resonance logging tool, wherein the positioning magnet is magnetically coupled with the ferrofluid to arrange the ferrofluid from the source to enhance or direct at least one magnetic field of the nuclear magnetic resonance logging tool.

6. The downhole system of claim 1 , further comprising at least two ferrofluid isolators positioned along a face of the tool body such that the ferrofluid is retained in a shape protruding from the face between the at least two ferrofluid isolators.

7. The downhole system of claim 1 , further comprising:
a first baffle positioned at a first end of the tool body;
a second baffle positioned at a second end of the tool body, the first baffle and the second baffle positioned to divert flow of wellbore fluid away from a sheltered region in the annulus, the sheltered region being positioned adjacent to the tool body and defined between the first baffle and the second baffle; and
a passageway positioned internal to the tool body and providing a flow path for wellbore fluid diverted by the first baffle and the second baffle to flow between the first end and the second end of the tool body, wherein the ferrofluid is positioned by the positioning magnet within the sheltered region of the annulus.

8. The downhole system of claim 1 , further comprising a ferrofluid collector positioned to collect ferrofluid in the annulus and communicate the ferrofluid to the source of the ferrofluid.

9. The downhole system of claim 1 , wherein the source is positioned to arrange the ferrofluid within the annulus by controlling a flow of the ferrofluid into a position in the annulus for magnetic coupling with the positioning magnet.

10. The downhole system of claim 1 , further comprising a system control center programmed with machine readable instructions to control the source of ferrofluid or the positioning magnet in arranging the ferrofluid within the annulus by at least one of providing commands to the source to introduce ferrofluid or providing commands to the positioning magnet to magnetically couple with the ferrofluid.

11. A downhole system comprising:
a tool body;
a sensor positioned in or connected with the tool body in a position for detecting changes in a magnetic field that extends through at least a portion of an annulus between the tool body and a wellbore formation;
a positioning magnet coupled with or in the tool body; and
a source of ferrofluid positioned to introduce ferrofluid through the tool body into the portion of the annulus and to arrange the ferrofluid within the portion of the annulus by controlling a flow of ferrofluid into a position in the annulus for magnetic coupling with the positioning magnet to enhance a magnetic field through at least the portion of the annulus so that the magnetic field differs in strength or direction in comparison to the magnetic field in the absence of the ferrofluid.

12. The downhole system of claim 11 , wherein the positioning magnet includes a first magnet and a second magnet positioned within the tool body and opposite one another with poles of the same polarity pointing together to produce an elongated magnetic field around the tool body so as to be magnetically coupled with the ferrofluid to arrange the ferrofluid in a radially omnidirectional shape about an exterior portion of the tool body.

13. The downhole system of claim 11 , wherein:
the source comprises a ferrofluid tank and a nozzle to communicate a flow of ferrofluid from the ferrofluid tank to the annulus, and
the downhole system further comprises:
a ferrofluid collector positioned to collect ferrofluid in the annulus from the source and to convey the collected ferrofluid to the ferrofluid tank; and
a ferrofluid filter in fluid communication with the ferrofluid collector such that the ferrofluid filter reduces wellbore fluids conveyed to the ferrofluid tank by the ferrofluid collector.

14. The downhole system of claim 11 , further comprising:
an upper ferrofluid isolator positioned along a face of the tool body and above the source of ferrofluid;
a lower ferrofluid isolator positioned along the face of the tool body and below the source of ferrofluid such that the ferrofluid is retained in a vertical region along the face of the tool body between the upper ferrofluid isolator and the lower ferrofluid isolator.

15. The downhole system of claim 11 , further comprising:
a first ferrofluid isolator positioned laterally in a first direction from the ferrofluid source along a face of the tool body;
a second ferrofluid isolator positioned laterally in a second direction from the ferrofluid source along the face of the tool body such that the ferrofluid is retained in a lateral region along the face of the tool body between the first ferrofluid isolator and the second ferrofluid isolator.

16. The downhole system of claim 11 , further comprising a system control center programmed with machine readable instructions to control the source of ferrofluid or the positioning magnet in arranging the ferrofluid within the annulus by at least one of providing commands to the source to control the flow of ferrofluid or providing commands to the positioning magnet to magnetically couple with the ferrofluid.

17. A system comprising:
a tool body;
a sensor positioned in or connected with the tool body in a position for detecting changes in a magnetic field that extends through at least a portion of an annulus between the tool body and a wellbore formation;
a ferrofluid source positioned to introduce ferrofluid through the tool body into the portion of the annulus;
a positioning magnet magnetically coupled to the ferrofluid in the portion of the annulus; and
a system control center programmed with machine readable instructions to control the f

Assignees

• Halliburton Energy Services Inc

Inventors

• Goodman George David
• Donderici Burkay
• Guner Baris

Classifications

• G01V3/32

  operating with electron or nuclear magnetic resonance · CPC title

• E21B47/18 Primary

  through the well fluid {, e.g. mud pressure pulse telemetry} · CPC title

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• G01V3/28

  using induction coils · CPC title

• E21B41/00 Primary

  Equipment or details not covered by groups E21B15/00 - E21B40/00 · CPC title