Electromagnetic telemetry gap sub assembly with insulating collar

Patent metadata

Field	Value
Publication number	US-10400520-B2
Application number	US-201815879214-A
Country	US
Kind code	B2
Filing date	Jan 24, 2018
Priority date	Nov 16, 2012
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

An insulating collar for a gap sub assembly for electromagnetic (EM) telemetry used in downhole drilling is disclosed. The gap sub assembly comprises a female member comprising a female mating section and a male member comprising a male mating section and a gap section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. The insulating collar is positioned on the gap section. The collar is made up of a framework with a plurality of discrete bodies spaced about the framework and a portion of each of the discrete bodies protrudes above the framework. Either the framework or the discrete bodies are made of an electrical insulator material to electrically isolate one end of the collar from the other end of the collar. The collar therefore electrically isolates the male member from the female member and the male member, female member and insulating collar function as the “gap sub” for EM telemetry.

First claim

What is claimed is:

1. An insulating collar for a gap sub assembly, the collar having first and second longitudinal ends spaced apart from each other and a bore extending longitudinally through the collar, the collar comprising:
a plurality of discrete bodies; and
a generally cylindrical framework configured to hold the discrete bodies at corresponding locations that are spaced apart from one another both circumferentially around and longitudinally along the framework such that a portion of each of the plurality of discrete bodies protrudes radially inwardly from an inside surface of the framework;
wherein the framework and the plurality of discrete bodies extend between the first and second longitudinal ends of the collar and one or both of the framework and the plurality of discrete bodies comprises an electrical insulator material so as to electrically isolate the first and second longitudinal ends of the collar from one another.

2. An insulating collar according to claim 1 wherein the framework comprises a plurality of parts made of a metal or metal alloy and the plurality of parts of the framework are separated from one another and electrically insulated from one another by some of the plurality of discrete bodies.

3. An insulating collar according to claim 1 wherein the plurality of discrete bodies are spheres.

4. An insulating collar according to claim 1 wherein the plurality of discrete bodies are made of ceramic.

5. An insulating collar according to claim 1 wherein the framework comprises plural rings spaced longitudinally apart along the collar, each of the rings having opposed side faces and some of the discrete bodies of the plurality of discrete bodies are located between each adjacent pair of the plurality of rings.

6. An insulating collar according to claim 5 wherein the side faces of the rings of each adjacent pair of the plurality of rings are shaped with features that fix circumferential positions of those of the discrete bodies located between the adjacent pair of the plurality of rings.

7. An insulating collar according to claim 5 wherein at least one of the rings is tapered in thickness such that an outer part of the at least one ring, furthest from the bore, is thicker than an inner part of the ring, closest to the bore.

8. An insulating collar according to claim 7 wherein the framework further comprises a dielectric material between the plurality of discrete bodies.

9. An insulating collar according to claim 1 wherein the framework comprises a pair of end rings and at least some of the discrete bodies of the plurality of discrete bodies are positioned between the end rings.

10. An insulating collar according to claim 9 wherein the framework further comprises one or more than one internal ring positioned between the pair of end rings, wherein at least some of the plurality of discrete bodies are positioned between each of the end rings and the internal ring.

11. An insulating collar according to claim 9 wherein each of the pair of end rings comprises an outer side face and an opposed inner side face with the inner side faces facing each other, each of the inner side faces including a plurality of spaced inner side face end ring surface depressions thereon, wherein each inner side face end ring surface depression is configured to receive a portion of one of the plurality of discrete bodies therein.

12. An insulating collar according to claim 11 wherein the outer side faces of the pair of end rings include a plurality of spaced outer side face end ring surface depressions thereon, wherein each outer side face end ring surface depression is configured to receive a portion of one of the plurality of discrete bodies therein.

13. An insulating collar according to claim 12 wherein the framework further comprises one or more than one internal ring positioned between the pair of end rings, wherein the internal ring comprises two opposed side faces with one of the opposed side faces facing the inner side face of one of the pair of end rings and the other of the opposed side faces facing the inner side face of the other of the pair of end rings, each of the opposed side faces including a plurality of spaced internal ring surface depressions thereon, wherein each internal ring surface depression is configured to receive a portion of one of the plurality of discrete bodies therein.

14. An insulating collar according to claim 13 wherein the internal rings have undulating side faces and the undulating side faces provide the internal ring surface depressions.

15. An insulating collar according to claim 13 wherein the internal ring surface depressions of one of the opposed side faces are offset from the internal ring surface depressions of the other of the opposed side faces.

16. An insulating collar according to claim 10 wherein the end rings are thicker than the internal ring.

17. An insulating collar according to claim 1 wherein the framework comprises a helical spring and at least some of the plurality of discrete bodies are positioned between inner side faces of the helical spring.

18. An insulating collar according to claim 1 wherein the framework comprises a sleeve with a plurality of holes therethrough and each of the plurality of holes receives at least a portion of one of the plurality of discrete bodies therethrough.

19. An insulating collar according to claim 1 wherein outward portions of at least some of the discrete bodies protrude radially outward past an outer surface of the framework and the outward portions comprise a material that may be used as a wear indicator.

20. An insulating collar according to claim 1 wherein the collar is at least 1 meter long.

21. A gap sub assembly comprising:
a female member having a female mating section;
a male member having a male mating section and a gap section, the male mating section being inserted into the female mating section whereby the male and female mating sections overlap;
an electrical isolator component located between the overlapping male and female mating sections such that the male and female members are mechanically coupled together but electrically isolated from each other at their mating sections; and
an insulating collar positioned on the gap section thereby electrically isolating the male member from the female member;
wherein the insulating collar comprises:
first and second longitudinal ends spaced apart from each other and a bore extending longitudinally through the collar;
a plurality of discrete bodies; and
a generally cylindrical framework configured to hold the discrete bodies at corresponding locations that are spaced apart from one another both circumferentially around and longitudinally along the framework such that a portion of each of the plurality of discrete bodies protrudes radially inwardly from an inside surface of the framework;

wherein the framework and the plurality of discrete bodies extend between the first and second longitudinal ends of the collar and one or both of the framework and the plurality of discrete bodies comprises an electrical insulator material so as to electrically isolate the first and second longitudinal ends of the collar from one another.

22. A gap sub assembly according to claim 21 wherein:
the male mating section has a first tapered section that gradually decreases in external diameter such that the external diameter of the first tapered section in an area adjacent to the gap section is greater than the external diameter of the first ta

Assignees

• Evolution Engineering Inc

Inventors

• Logan Aaron W
• Ahmoye Daniel W
• Switzer David A
• Logan Justin C
• Derkacz Patrick R
• Kazemi Miraki Mojtaba

Classifications

• F16L25/02

  specially adapted for electrically insulating the two pipe ends of the joint from each other · CPC title

• F16L25/021

  for screw-threaded joints · CPC title

• F16L15/08

  with supplementary elements (F16L15/04 takes precedence) · CPC title

• E21B17/042

  Threaded · CPC title

• F16L2201/40

  for special environments · CPC title