Self relieving seal

• US 20040040747A1
• Filed: 04/02/2003
• Published: 03/04/2004
• Est. Priority Date: 04/03/2002
• Status: Active Grant

• Current Assignee: Smith International Incorporated (Schlumberger NV)
• Original Assignee: Smith International Incorporated (Schlumberger NV)
• Inventors: Griffo, Anthony, Cariveau, Peter T., Larsen, James L., White, Alysia C., Peterson, Steven W., Lockstedt, Alan, Neville, James L., Siracki, Michael, Bandi, Manikiran
• Granted Patent: US 6,976,548 B2
• Time in Patent Office: Days
• US Class Current: 175/57
• CPC Class Codes: E21B 10/25 characterised by sealing details
• CPC Class Codes: Y10S 277/926 Seal including fluid pressure equalizing or balancing feature
• CPC Class Codes: Y10S 277/928 Seal including pressure relief or vent feature

Abstract

Self relieving seals of this invention comprise an elastomeric seal body having a first sealing surface and a second sealing surface for contact with respective drill bit sealing surfaces. The seal includes a pair of external surfaces that each extend along the seal body between the first and second sealing surfaces. The seal includes one or more relief ports that are disposed through the seal body and that have openings through each of the seal body external surfaces. The relief port can be specially configured, e.g., have different diameter sections of constant or variable dimensions, to provide a degree of control over pressure equalization through the seal body when the seal is loaded within the drill bit. The seal may include an element, e.g., solid, tubular, or porous, disposed within the relief port to provide a further desired degree of control over pressure equalization through the seal when the seal is loaded within the drill bit. Surface features, on the seal or the drill bit, can be provided to offset the relief port opening from the rock bit so that it is not blocked off. The seal can include a valve mechanism to provide a further degree of control over fluid passage through the relief port.

Claims

1. An annular seal for use in a rotary cone drill bit comprising:

an elastomeric seal body having a first sealing surface and a second sealing surface for contact with respective drill bit sealing surfaces, and a pair of external surfaces each extending along the seal body between the first and second sealing surfaces; and

one or more relief ports disposed through the seal body and having openings through each of the seal body external surfaces.

2. The annular seal as recited in claim 1 wherein the relief port comprises two or more different diameter sections.

3. The annular seal as recited in claim 1 wherein the relief port comprises a first diameter section that extends into the seal body a distance from one seal body external surface, and a second diameter section that extends from the first constant diameter section to the other seal body external surface and that is greater in diameter than the first diameter section.

4. The annular seal as recited in claim 3 wherein the first diameter section has a constant diameter, and the second diameter section has a variable diameter.

5. The annular seal as recited in claim 1 wherein the seal body includes a tubular element that is at least partially disposed within the relief port, the tubular element having a central passage extending therethrough.

6. The annular seal as recited in claim 5 wherein the tubular element is formed from a rigid material for reinforcing the relief port.

7. The annular seal as recited in claim 5 wherein the tubular element is formed from a flexible material having a low coefficient of friction.

8. The annular seal as recited in claim 1 wherein the relief port includes an element disposed therein for providing a fluid transport conduit within the relief port.

9. The annular seal as recited in claim 8 wherein the seal body includes a surface feature adjacent each relief port opening that increases the surface area of each relief port opening at the external surfaces.

10. The annular seal as recited in claim 1 further comprising an element disposed within the relief port for forming an annular space within the seal body.

11. The annular seal as recited in claim 10 wherein the element disposed within the relief port is formed from a flexible material.

12. The annular seal as recited in claim 10 wherein the element disposed within the relief port is formed from a rigid material.

13. The annular seal as recited in claim 1 further comprising a porous element connected with the seal body and in connection with the relief port.

14. The annular seal as recited in claim 1 wherein the seal body includes a raised surface feature positioned along at least one of the external surfaces adjacent the relief port opening to prevent the opening from being sealed against an adjacent bit surface.

15. The annular seal as recited in claim 1 further comprising a valve means disposed within the relief port to provide checked one-way flow therethrough.

16. A rotary cone drill bit comprising:

a body having at least one leg extending therefrom;

cutting cones rotatably disposed on an end of the leg; and

one or more annular seals interposed between the cutting cone and leg in one or more seal glands, at least one seal comprising;

an elastomeric seal body having a first sealing surface and a second sealing surface for contacting respective drill bit sealing surfaces, and a pair external surfaces each extending along the seal body between the first and second sealing surfaces; and

one or more relief ports disposed through the seal body and having openings through each of the seal body external surfaces.

17. The drill bit as recited in claim 16 wherein the seal gland includes means for facilitating pressure communication with the seal body relief port.

18. The drill bit as recited in claim 17 wherein the means include:

a first groove disposed within a wall surface of the seal gland and extending circumferentially along the wall surface; and

one or more second grooves disposed within the seal gland wall surface and extending radially from the first groove to a position adjacent an edge of the seal gland.

19. The drill bit as recited in claim 16 wherein the relief port comprises two or more different diameter sections.

20. The drill bit as recited in claim 19 wherein the relief port comprises a first diameter section that extends into the seal body a distance from one seal body external surface, and a second diameter section that extends from the first diameter section to the other seal body external surface.

21. The drill bit as recited in claim 20 wherein the second diameter section is larger than the first diameter section.

22. The drill bit as recited in claim 20 wherein the second diameter section has a variable diameter and the first diameter section has a constant diameter.

23. The drill bit as recited in claim 16 wherein the seal body includes a tubular element that is at least partially disposed within the relief port.

24. The drill bit as recited in claim 23 wherein the tubular element is formed from a rigid material for reinforcing the relief port.

25. The drill bit as recited in claim 23 wherein the tubular element is formed from a flexible material having a low coefficient of friction.

26. The drill bit as recited in claim 16 wherein the relief port includes an element disposed therein for providing a fluid transport conduit within the relief port.

27. The drill bit as recited in claim 26 wherein the seal body includes a surface feature adjacent each relief port opening that increases the surface area of each relief port opening at the external surfaces.

28. The drill bit as recited in claim 16 further comprising an element disposed within the relief port for forming an annular space within the seal body.

29. The drill bit as recited in claim 28 wherein the element disposed within the relief port is formed from a flexible material.

30. The drill bit as recited in claim 28 wherein the element disposed within the relief port is formed from a rigid material.

31. The drill bit as recited in claim 16 further comprising a porous element connected with the seal body and in communication with the relief port.

32. The drill bit as recited in claim 16 wherein the seal body includes a raised surface feature positioned along at least one of the external surfaces adjacent the relief valve opening to prevent the opening from being sealed against an adjacent bit surface.

33. The drill bit as recited in claim 16 further comprising a valve means disposed within the relief port to provide checked one-way flow therethrough.

34. A dual seal rotary cone drill bit comprising a primary annular seal as recited in claim 16 positioned within the bit adjacent a journal bearing of the drill bit, and a secondary seal positioned within the bit between the primary annular seal and a bit external environment, wherein the primary seal.

57. The method as recited in claim 26 further comprising controlling the passage of fluid or gas through the relief port until a desired threshold is achieved.

35. A rotary cone drill bit comprising:

a body having at least one leg extending therefrom, the leg having a journal segment;

a cutting cone rotatably disposed on the journal segment and forming a bearing cavity therebetween an annular primary seal disposed between the leg and roller cone;

an annular secondary seal disposed between the leg and roller cone, and between the annular primary seal and a borehole, at least one of the seals comprising;

an elastomeric seal body having a first sealing surface and a second sealing surface for contacting respective drill bit sealing surfaces, and a pair external surfaces each extending along the seal body between the first and second sealing surfaces; and

one or more relief ports disposed through the seal body and having openings through each of the seal body external surfaces.

36. The drill bit as recited in claim 35 wherein the annular primary seal comprises the one or more relief ports.

37. The drill bit as recited in claim 35 wherein the annular secondary seal comprises the one or more relief ports.

38. The drill bit as recited in claim 35 further comprising means for facilitating pressure communication with the seal body relief port.

39. The drill bit as recited in claim 38 wherein the means include:

a first groove disposed within a drill bit wall surface and extending circumferentially therealong; and

one or more second grooves disposed within the wall surface and extending radially from the first groove to a position adjacent an edge of the wall surface.

40. The drill bit as recited in claim 35 wherein the relief port comprises two or more different diameter sections.

41. The drill bit as recited in claim 36 wherein the relief port comprises a first diameter section that extends into the seal body a distance from one seal body external surface, and a second diameter section that extends from the first diameter section to the other seal body external surface.

42. The drill bit as recited in claim 41 wherein the second diameter section is larger than the first diameter section.

43. The drill bit as recited in claim 41 wherein the second diameter section has a variable diameter and the first diameter section has a constant diameter.

44. The drill bit as recited in claim 35 wherein the seal body includes a tubular element that is at least partially disposed within the relief port.

45. The drill bit as recited in claim 44 wherein the tubular element is formed from a rigid material for reinforcing the relief port.

46. The drill bit as recited in claim 44 wherein the tubular element is formed from a flexible material having a low coefficient of friction.

47. The drill bit as recited in claim 35 wherein the relief port includes an element disposed therein for providing a fluid transport conduit within the relief port.

48. The drill bit as recited in claim 47 wherein the seal body includes a surface feature adjacent each relief port opening that increases the surface area of each relief port opening at the external surfaces.

49. The drill bit as recited in claim 35 further comprising an element disposed within the relief port for forming an annular space within the seal body.

50. The drill bit as recited in claim 49 wherein the element disposed within the relief port is formed from a flexible material.

51. The drill bit as recited in claim 49 wherein the element disposed within the relief port is formed from a rigid material.

52. The drill bit as recited in claim 35 further comprising a porous element connected with the seal body and in communication with the relief port.

53. The drill bit as recited in claim 35 wherein the seal body includes a raised surface feature positioned along at least one of the external surfaces adjacent the relief valve opening to prevent the opening from being sealed against an adjacent bit surface.

54. The drill bit as recited in claim 35 further comprising a valve means disposed within the relief port to provide checked one-way flow therethrough.

55. The drill bit as recited in claim 35 further comprising a valve means disposed within the relief port to provide checked one-way flow therethrough.

56. A method for equalizing differential pressure imposed on an annular seal disposed within a rotary cone drill bit by passing fluid or gas from a region of high pressure, existing on one side of the seal, to a region of relatively lower pressure, existing on another side of the seal, through a relief port formed through a body portion of the seal, wherein the relief port extends between external surfaces of the seal body, the seal body external surfaces existing between a seal body first sealing surface and a second sealing surface in contact with respective drill bit sealing surfaces.