Inductive cavity sensors for resistivity tools

Patent metadata

Field	Value
Publication number	US-10641087-B2
Application number	US-201515749842-A
Country	US
Kind code	B2
Filing date	Oct 28, 2015
Priority date	Oct 28, 2015
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A first magnetic cavity transmitter is in the conductive tool body. A first magnetic cavity receiver is in the conductive tool body. A first transmit module is coupled to the first magnetic cavity transmitter. A first receiver module is coupled to the first magnetic cavity receiver.

First claim

What is claimed is:

1. An apparatus comprising:
a conductive tool body comprising:
a first transmitter comprising:
a first transmitter annular cavity that encircles the conductive tool body,
a first transmitter surface gap that encircles the conductive tool body and electromagnetically couples the first transmitter annular cavity to an external surface of the conductive tool body, and
a first transmitter ring of high magnetic permeability material in the first transmitter annular cavity;

a first receiver comprising:
a first receiver annular cavity,
a first receiver surface gap that electromagnetically couples the external surface of the conductive tool body to the first receiver annular cavity, and
a first high magnetic permeability material in the first receiver annular cavity;

a first transmitter module coupled to opposite sides of the first transmitter surface gap to induce an electric current around the first transmitter annular cavity; and
a first receiver module coupled to opposite sides of the first receiver surface gap to detect currents induced around the first receiver annular cavity.

2. The apparatus of claim 1 wherein the first transmitter emulates a toroid transmitter and the first receiver emulates a toroid receiver.

3. The apparatus of claim 1 further comprising:
a second transmitter in the conductive tool body; and
a second transmit module coupled to the second transmitter.

4. The apparatus of claim 1 further comprising:
a second receiver in the conductive tool body; and
a second receive module coupled to the second receiver.

5. The apparatus of claim 1 further comprising:
a second transmitter in the conductive tool body;
a second receiver in the conductive tool body;
a second transmit module coupled to the second transmitter; and
a second receive module coupled to the second receiver.

6. The apparatus of claim 1 wherein the conductive tool body further comprises:
a second transmitter comprising:
a second transmitter annular cavity that encircles the conductive tool body,
a second transmitter surface gap that encircles the conductive tool body and electromagnetically couples the second transmitter annular cavity to the external surface of the conductive tool body, and
a second transmitter ring of high magnetic permeability material in the second transmitter annular cavity.

7. The apparatus of claim 6 further comprising:
a second transmitter module coupled to opposite sides of the second transmitter surface gap to induce an electric current around the second transmitter annular cavity.

8. The apparatus of claim 1 wherein the conductive tool body further comprises:
a second receiver comprising:
a second receiver cavity,
a second receiver surface gap that electromagnetically couples the external surface of the conductive tool body to the second receiver cavity, and
a second high magnetic permeability material in the second receiver annular cavity.

9. The apparatus of claim 8 further comprising:
a second receiver module coupled to opposite sides of the second receiver surface gap to detect currents induced around the second receiver annular cavity.

10. The apparatus of claim 1 , wherein:
the conductive tool body further comprises:
a second transmitter comprising:
a second transmitter annular cavity that encircles the conductive tool body,
a second transmitter surface gap that encircles the conductive tool body and electromagnetically couples the second transmitter annular cavity to the external surface of the conductive tool body, and
a second transmitter ring of high magnetic permeability material in the second transmitter annular cavity;

a second receiver comprising:
a second receiver cavity,
a second receiver surface gap that electromagnetically couples the external surface of the conductive tool body to the second receiver annular cavity, and
a second receiver ring of high magnetic permeability material in the second receiver annular cavity;

the apparatus further comprises:
a second transmitter module coupled to opposite sides of the second transmitter surface gap to induce an electric current around the second transmitter annular cavity; and
a second receiver module coupled to opposite sides of the second receiver surface gap to detect currents induced around the second receiver annular cavity.

11. The apparatus of claim 10 wherein:
the first receiver annular cavity is a large cavity and the second receiver annular cavity is a small cavity, wherein the large cavity is at least 10 percent larger than the small cavity.

12. The apparatus of claim 10 wherein:
the first receiver and the second receiver are longitudinally between the first transmitter and the second transmitter on the conductive tool body.

13. The apparatus of claim 12 wherein:
the first transmitter and the second transmitter are symmetrically located around the first receiver and the second receiver.

14. The apparatus of claim 1 further comprising:
a processor coupled to the first receiver module to calculate resistivity based on a signal received from the first received from the first receiver module.

15. The apparatus of claim 1 wherein the first receiver module comprises a high impedance load.

16. An apparatus comprising:
a conductive tool body;
a first magnetic cavity transmitter in the conductive tool body;
a first magnetic cavity receiver in a member coupled to the conductive tool body;
a first transmit module coupled to the first magnetic cavity transmitter;
a first receiver module coupled to the first magnetic cavity receiver;
wherein the first magnetic cavity transmitter includes:
a first transmitter annular cavity that encircles the conductive tool body;
a first transmitter surface gap that encircles the conductive tool body and electromagnetically couples the first transmitter annular cavity to an external surface of the conductive tool body;

wherein the first magnetic cavity receiver includes:
a first receiver annular cavity;
a first receiver surface gap that electromagnetically couples the external surface of the member to the first receiver annular cavity; and
a first high magnetic permeability material in the first receiver annular cavity;

wherein the first transmitter module is coupled to opposite sides of the first transmitter surface gap to induce an electric current around the first transmitter annular cavity; and
wherein the first receiver module coupled to opposite sides of the first receiver surface gap to detect currents induced around the first receiver annular cavity.

17. The apparatus of claim 16 wherein the member is a stabilizer.

Assignees

• Halliburton Energy Services Inc

Inventors

• Wilson Glenn Andrew
• Ma Jin
• Pan Li

Classifications

• E21B49/00 Primary

  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

• E21B47/024

  of devices in the borehole (determining slope or direction of the borehole E21B47/022) · CPC title

• E21B47/16

  through the drill string or casing {, e.g. by torsional acoustic waves} · CPC title

• E21B47/13

  by electromagnetic energy, e.g. radio frequency · CPC title

• G01V3/26 Primary

  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