Floating plug pressure equalization in oilfield drill bits

Patent metadata

Field	Value
Publication number	US-9359822-B2
Application number	US-201414279065-A
Country	US
Kind code	B2
Filing date	May 15, 2014
Priority date	Dec 14, 2011
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A drill bit of the type used to drill a wellbore in the earth can comprise a bore formed in the drill bit, and a plug sealingly and reciprocably disposed in the bore, whereby the plug prevents fluid communication between sections of the bore in the drill bit. The plug can comprise a spherically-shaped member. The plug can comprise a floating plug sealingly and reciprocably disposed in the bore, whereby pressure in the different sections of the bore on respective opposite sides of the plug is substantially equalized.

First claim

What is claimed is:

1. A wellbore drill bit, comprising:
an annular gap between a journal and a cone;
a lubricant disposed in the annular gap;
at least one seal having two sides and disposed between the journal and the cone to prevent the lubricant from escaping the annular gap;
a bore formed in the drill bit and having a first section in fluid communication with a first side of the seal and a second section in fluid communication with a second side of the seal; and
a spherical plug having an entire exterior surface made of a resilient material, the resilient material comprising an elastomer, the spherical plug sealingly and reciprocably disposed in the bore, whereby the spherical plug slidingly displaces within the bore in response to a pressure differential between the first section and the second section to equalize pressure on both sides of the seal, while preventing fluid communication between the first section and the second section.

2. The wellbore drill bit of claim 1 , further comprising at least a second seal that, in conjunction with the first seal, seals off the annular gap, wherein the first section is in fluid communication with the annular gap.

3. The drill bit of claim 2 , wherein the second section is in fluid communication with the annular gap.

4. The drill bit of claim 2 , wherein the second section is in fluid communication with a lubricant chamber in the drill bit.

5. The wellbore drill bit of claim 1 , wherein the spherical plug is formed entirely of the elastomer.

6. The wellbore drill bit of claim 1 , wherein the second section is in fluid communication with an exterior of the drill bit.

7. A wellbore drill bit, comprising:
an annular gap between a journal and a cone;
a lubricant disposed in the annular gap;
at least one seal having two sides and disposed between the journal and the cone to prevent the lubricant from escaping the annular gap;
a first bore formed in the drill bit and having a first section in fluid communication with a first side of the seal and a second section in fluid communication with a second side of the seal;
a first plug having an entire exterior surface made of a resilient material, the resilient material comprising an elastomer, the first plug sealingly and reciprocably disposed in the first bore, whereby the first plug slidingly displaces within the first bore in response to a pressure differential between the first section and the second section to equalize pressure on both sides of the seal, while preventing fluid communication between the first section and the second section;
a second bore formed in the drill bit and having an internal section in fluid communication with the first bore and an external section in fluid communication with an exterior of the drill bit; and
a second plug having an entire exterior surface made of a resilient material, the resilient material comprising an elastomer, the second plug sealingly and reciprocably disposed in the second bore, whereby the plug slidingly displaces within the second bore in response to a pressure differential between the internal section and external section to equalize pressure between the internal section and the external section, while preventing fluid communication between the external section and the internal section,
wherein the first plug, the second plug, or both is spherical.

8. The drill bit of claim 7 , wherein the second section is in fluid communication with the annular gap.

9. The drill bit of claim 7 , wherein the second section is in fluid communication with a lubricant chamber in the drill bit.

10. The wellbore drill bit of claim 7 , wherein the first plug, the second plug, or both is formed entirely of the elastomer.

11. The wellbore drill bit of claim 7 , further comprising a retainer in the external section to prevent the second plug from being discharged out of the second bore.

12. The wellbore drill bill of claim 7 , further comprising:
a lubricant chamber containing the lubricant in fluid communication with the first bore; and
a bypass chamber at an end of the internal section to receive the second plug if sufficient lubricant is lost from the lubricant chamber.

13. The wellbore drill bit of claim 7 , further comprising:
a lubricant chamber containing the lubricant in fluid communication with the second bore; and
a valve comprising:
the second plug;
a biasing device; and
a recess to allow the lubricant to bypass the second plug and enter the external section when the second plug is displaced against a biasing force exerted by the biasing device.

14. A wellbore drill bit, comprising:
a bore formed in the drill bit and having a first section in fluid communication with an interior of the drill bit and a second section in fluid communication with an exterior of the drill bit; and
a spherical plug formed entirely of an elastomer, the spherical plug sealingly and reciprocably disposed in the bore, whereby the spherical plug slidingly displaces within the bore in response to a pressure differential between the first section and second section to equalize pressure between the first section and the second section, while preventing fluid communication between the first section and the second section.

15. The wellbore drill bit of claim 14 , further comprising a retainer in the external section to prevent the spherical plug from being discharged out of the second bore.

16. The wellbore drill bill of claim 14 , further comprising:
a lubricant chamber containing the lubricant in fluid communication with the first bore; and
a bypass chamber at an end of the internal section to receive the spherical plug if sufficient lubricant is lost from the lubricant chamber.

17. The wellbore drill bill of claim 14 , further comprising:
a lubricant chamber containing lubricant in fluid communication with the bore; and
a valve comprising:
the spherical plug;
a biasing device; and
a recess to allow lubricant to bypass the spherical plug and enter the external section when the spherical plug is displaced against a biasing force exerted by the biasing device.

18. A wellbore drill bit, comprising:
an annular gap between a journal and a cone;
a lubricant disposed in the annular gap;
at least one seal having two sides and disposed between the journal and the cone to prevent the lubricant from escaping the annular gap;
a bore formed in the drill bit and having a first section in fluid communication with a first side of the seal and a second section in fluid communication with a second side of the seal; and
a spherical plug sealingly and reciprocably disposed in the bore such that the spherical plug can rotate within the bore without binding, and while maintaining sealing engagement with the bore, whereby the spherical plug slidingly displaces within the bore in response to a pressure differential between the first section and the second section to equalize pressure on both sides of the seal, while preventing fluid communication between the first section and the second section regardless of plug orientation.

19. The drill bit of claim 18 , wherein the second section is in fluid communication with the annular gap.

20. The drill bit of 18 , wherein the second section is in fluid communication with a lubricant chamber in the drill bit.

21. The wellbore drill bit of claim 18 , further comprising at least a second seal that, in conjunction with the first seal, seals off the annular gap, wherein the first section is in fluid communication with the annular gap.

Assignees

• Halliburton Energy Services Inc

Inventors

• Crawford Micheal B

Classifications

• E21B10/60

  characterised by conduits or nozzles for drilling fluids (for roller bits E21B10/18; for percussion drill bits E21B10/38) · CPC title

• E21B10/25 Primary

  characterised by sealing details · CPC title

• E21B10/00

  Drill bits (specially adapted for deflecting the direction of boring {E21B7/064}; with means for collecting substances E21B27/00) · CPC title

• E21B10/24 Primary

  characterised by lubricating details (E21B10/23 takes precedence) · CPC title