Electromagnetic telemetry gap sub assembly with insulating collar

Patent metadata

Field	Value
Publication number	US-9909369-B2
Application number	US-201314443173-A
Country	US
Kind code	B2
Filing date	Nov 15, 2013
Priority date	Nov 16, 2012
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

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. A gap sub comprising:
a first end comprising a first coupling and a second end comprising a second coupling, the first and second ends attached to and electrically insulated from one another;
a reduced-diameter section extending between and connecting the first and second ends; and
a collar extending circumferentially around and along the reduced-diameter section, the collar comprising:
a plurality of metal rings, the plurality of metal rings being axially spaced apart from one another and radially spaced from the reduced-diameter section by electrically-insulating bodies disposed between adjacent ones of the plurality of rings; and
a dielectric material filling voids between the metal rings.

2. A gap sub according to claim 1 wherein the electrically-insulating bodies comprise ceramic spheres.

3. A gap sub according to claim 1 wherein one or more ring of the plurality of rings has a side face formed such that an axial spacing between the one or more ring and an adjacent one of the plurality of rings increases with distance from an exterior face of the ring.

4. A gap sub according to claim 1 wherein one or more ring of the plurality of rings has a cross section formed such that the cross section becomes narrower toward the center of the ring.

5. A gap sub according to claim 4 wherein side faces of the one or more ring is beveled.

6. A gap sub according to claim 1 wherein the plurality of rings have side faces formed to provide recesses and the electrically-insulating bodies are engaged with the recesses.

7. A gap sub according to claim 6 wherein the plurality of rings have undulating side faces and the undulating side faces provide the recesses.

8. A gap sub according to claim 6 wherein in at least some of the plurality of rings the recesses on a first side face of the ring are angularly offset from the recesses on a second side face of the ring opposed to the first side face.

9. A gap sub according to claim 1 comprising first and second shoulders respectively at first and second ends of the reduced-diameter portion wherein the collar is preloaded in compression to bear against the first and second collars with a preload pressure.

10. A gap sub according to claim 9 comprising a plurality of wedges configured to provide the preload pressure by being inserted between the first shoulder and the collar and/or the second shoulder and the collar.

11. A gap sub according to claim 9 wherein the first and second couplings comprise first and second threaded couplings, and wherein the first and second threaded couplings are configured to provide the preload pressure by drawing the male shoulder toward the female shoulder when the first end is turned relative to the second end.

12. A gap sub according to claim 9 comprising one or more chords extending across the collar, wherein the chords are configured to provide the preload pressure.

13. A gap sub according to claim 9 comprising an annular member adjacent to either the first shoulder or the second shoulder and extending circumferentially around the reduced diameter section, wherein the annular member comprises a threaded portion that engages a corresponding threaded portion on the reduced diameter section, and wherein the annular member is configured to provide the preload pressure when the annular member is turned relative to the reduced diameter section.

14. A gap sub according to claim 13 wherein there are one or more holes passing through the annular member configured to facilitate filling the areas on both sides of the annular member with a dielectric material.

15. A gap sub according to claim 9 wherein one of the first and second shoulders is coupled for axial movement along the reduced-diameter section.

16. A gap sub according to claim 9 wherein the preload pressure is at least 500 psi.

17. A gap sub according to claim 1 wherein the first and second couplings comprise a threaded coupling.

18. A gap sub according to claim 1 wherein the first and second couplings comprise a pinned coupling.

19. A gap sub according to claim 18 wherein the pined coupling comprises a plurality of pins, each of the plurality of pins inserted into one of a plurality of apertures in the first end and one of a plurality of bores in the second end.

20. A gap sub according to claim 19 wherein at least a first one of the plurality of pins is non-conductive.

21. A gap sub according to claim 19 wherein at least a second one of the plurality of pins is conductive.

22. A gap sub according to claim 21 wherein the second one of the plurality of pins is electrically coupled to the first end and electrically insulated from the second end.

23. A gap sub according to claim 21 wherein the second one of the plurality of pins is electrically coupled to the second end, and electrically insulated from the first end.

24. A gap sub according to claim 1 , wherein the first and second couplings comprise a pinned coupling, wherein the pinned coupling comprises a plurality of pins extending out of the first end into a corresponding plurality of bores in the second end.

25. A gap sub according to claim 24 wherein the plurality of pins are electrically conductive, and wherein an insulating material prevents the plurality of pins from directly touching the second end.

26. A gap sub according to claim 1 wherein:
the first coupling comprises a first plurality of grooves on the exterior surface of the reduced-diameter section;
the second coupling comprises a second plurality of grooves on the interior surface of a bore of the second end;
the first end is coupled to the second end by a plurality of coupling bodies; and
each of the plurality of coupling bodies extends into one of the first plurality of grooves and extends into one of the second plurality of grooves.

27. A gap sub according to claim 26 wherein:
at least one of the first plurality of grooves comprises a first longitudinal groove that extends longitudinally along the exterior surface of the reduced-diameter section;
at least one of the second plurality of grooves comprises a second longitudinal groove that extends longitudinally along the interior surface of the bore of the second end; and
at least a first one of the plurality of coupling bodies extends into both the first longitudinal groove and the second longitudinal groove to resist relative rotational movement of the first end and the second end.

28. A gap sub according to claim 26 wherein:
at least one of the first plurality of grooves comprises a first circumferential groove that extends circumferentially around the exterior surface of the reduced-diameter section;
at least one of the second plurality of grooves comprises a second circumferential groove that extends circumferentially around the interior surface of the bore of the second end; and
at least a second one of the plurality of coupling bodies extends into both the first circumferential groove and the second circumferential groove to resist relative longitudinal movement of the first end and the second end.

29. A gap sub according to claim 26 wherein:
at least one of the first plurality of grooves comprises a first helical groove that extends helically around the exterior surface of the reduced-diameter section;
at least one of the second plurality of grooves comprises a second helical groove that extend

Assignees

• Evolution Engineering Inc

Inventors

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

Classifications

• F16L25/021

  for screw-threaded joints · CPC title

• F16L25/02

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

• F16L2201/40

  for special environments · CPC title

• F16L15/08

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

• E21B17/003 Primary

  with electrically conducting or insulating means (E21B17/028 and E21B17/023 take precedence) · CPC title