Expandable reamer apparatus for enlarging boreholes while drilling and methods of use Number:7,036,611 from the United States Patent and Trademark Office (PTO) owispatent An expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade carried by a tubular body may be selectively positioned at an inward position and an expanded position. The laterally movable blade, held inwardly by blade-biasing elements, may be forced outwardly by drilling fluid selectively allowed to communicate therewith by way of an actuation sleeve disposed within the tubular body. Alternatively, a separation element may transmit force or pressure from the drilling fluid to the movable blade. Further, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad, fixed bearing pad preceding the movable blade, or an adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated.<H Expandable, boreholes, Expandable, ream, 7036611.html, Patent, pto, 7036611

Title: Expandable reamer apparatus for enlarging boreholes while drilling and methods of use

Abstract: An expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade carried by a tubular body may be selectively positioned at an inward position and an expanded position. The laterally movable blade, held inwardly by blade-biasing elements, may be forced outwardly by drilling fluid selectively allowed to communicate therewith by way of an actuation sleeve disposed within the tubular body. Alternatively, a separation element may transmit force or pressure from the drilling fluid to the movable blade. Further, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad, fixed bearing pad preceding the movable blade, or an adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated.

Patent Number: 7,036,611 Issued on 05/02/2006 to Radford, et al.

Inventors: Radford; Steven R. (The Woodlands, TX); Ireland; Kelly D. (The Woodlands, TX); Gautam; Anurag (Cypress, TX); Laing; Robert A. (Montgomery, TX); Mumma; Matthew D. (Spring, TX); Pritchard; Daryl L. (Shenandoah, TX)
Assignee: Baker Hughes Incorporated (Houston, TX)

Appl. No.: 624952

Filed: July 22, 2003

Current U.S. Class: 175/57 ; 175/296; 175/406

Current International Class: E21B 10/32 (20060101)

Field of Search: 175/57,296,297,298,385,406

References Cited [Referenced By]

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Primary Examiner: Neuder; William
Attorney, Agent or Firm: TraskBritt

Parent Case Text

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/399,531, filed Jul. 30, 2002, for EXPANDABLE REAMER APPARATUS FOR ENLARGING BOREHOLES WHILE DRILLING AND METHOD OF USE.

Claims

What is claimed is:

1. An expandable reamer for drilling a subterranean formation, comprising: a tubular body having a longitudinal axis a drilling fluid flow path extending through the expandable reamer for conducting drilling fluid therethrough; a plurality of generally radially and longitudinally extending blades carried by the tubular body, carrying at least one cutting structure thereon, wherein at least one blade of the plurality of blades is laterally movable; at least one blade-biasing element configured for providing a biasing force oriented substantially transversely to the longitudinal axis and in contact with the at least one laterally movable blade for holding the at least one laterally movable blade at an innermost lateral position with a force, the innermost lateral position corresponding to no more than an initial diameter of the expandable reamer; structure for preventing lateral movement of the at least one laterally movable blade beyond an outermost lateral position corresponding to an expanded diameter of the expandable reamer; and an actuation sleeve positioned along an inner diameter of the tubular body and configured to selectively allow communication of drilling fluid passing through the tubular body with the at least one laterally movable blade to effect outward lateral movement thereof responsive to a force or pressure of drilling fluid passing through the tubular body.

2. The expandable reamer of claim 1, further comprising at least one fluid aperture disposed within the at least one laterally movable blade for communicating drilling fluid from an interior of the tubular body to an outer surface of the at least one laterally movable blade.

3. The expandable reamer of claim 2, wherein the at least one fluid aperture is oriented at an angle from a horizontal plane perpendicular to the longitudinal axis and toward the trailing end of the tubular body.

4. The expandable reamer of claim 1, wherein the at least one cutting structure comprises a plurality of superabrasive cutters.

5. The expandable reamer of claim 1, wherein the at least one cutting structure comprises a tungsten carbide compact.

6. The expandable reamer of claim 1, wherein the actuation sleeve is configured to increase a size of the drilling fluid flow path through the expandable reamer by way of selectively allowing drilling fluid communication with at least one alternative drilling fluid flow path while allowing drilling fluid to communicate with the at least one laterally movable blade.

7. The expandable reamer of claim 1, wherein a cross-sectional shape of the at least one laterally movable blade in a geometric plane substantially perpendicular to the lateral movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

8. The expandable reamer of claim 1, wherein a cross-sectional shape of a portion of the at least one laterally movable blade capable of being positioned laterally outside of the tubular body in a geometric plane substantially perpendicular to the direction of lateral movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

9. The expandable reamer of claim 1, further comprising: a reduced cross-sectional area orifice for developing longitudinal force upon the actuation sleeve by way of drilling fluid flowing therethrough; wherein a first longitudinal position of the actuation sleeve prevents drilling fluid from communicating with the at least one laterally movable blade and a second longitudinal position of the actuation sleeve allows drilling fluid to communicate with the at least one laterally movable blade.

10. The expandable reamer of claim 9, wherein the reduced cross-sectional area orifice is sized and configured to generate a selected magnitude of longitudinal force upon the actuation sleeve in relation to an expected drilling fluid flow rate.

11. The expandable reamer of claim 9, further comprising an actuation sleeve-biasing element for positioning the actuation sleeve in the first longitudinal position with a force.

12. The expandable,reamer of claim 11, further comprising a pin affixed to the actuation sleeve, the pin disposed within a-groove formed within a pin guide sleeve configured to selectively position the actuation sleeve.

13. The expandable reamer of claim 12, wherein the groove comprises alternating upward sloping and downward sloping arcuate paths formed at least partially along a circumference of the pin guide sleeve.

14. The expandable reamer of claim 13, wherein the actuation sleeve-biasing element and the reduced cross-sectional orifice are sized and configured so that a drilling fluid flow rate equal to or exceeding a first selected value causes the pin and actuation sleeve to be longitudinally displaced substantially to a lower longitudinal extent of its associated arcuate path; and wherein the first longitudinal position of the actuation sleeve substantially corresponds with an upper longitudinal extent of at least one arcuate path formed at least partially along the circumference of the pin guide sleeve.

15. The expandable reamer of claim 14, wherein the actuation sleeve-biasing element and the reduced cross-sectional orifice are sized and configured so that a drilling fluid flow rate of a second selected value lower than the first selected value causes the pin and actuation sleeve to be longitudinally displaced about halfway between the first longitudinal position of the actuation sleeve and the second longitudinal position of the actuation sleeve.

16. The expandable reamer of claim 9, wherein the actuation sleeve is sized and configured so that at the first longitudinal position, an upper longitudinal end of the actuation sleeve is above or within the longitudinal extent of the at least one laterally movable blade, and at the second longitudinal position, the actuation sleeve is positioned longitudinally outside of the longitudinal extent of the at least one laterally movable blade.

17. The expandable reamer of claim 9, wherein the second longitudinal position of the actuation sleeve increases a size of the drilling fluid flow path through the expandable reamer by way of selectively allowing drilling fluid communication with at least one alternative drilling fluid flow path while allowing drilling fluid to communicate with the at least one laterally movable blade.

18. The expandable reamer of claim 1, wherein the actuation sleeve is configured to accept or interact with a restriction element for selectively activating the actuation sleeve by preventing flow of drilling fluid therethrough to cause the actuation sleeve to move and allow the communication of drilling fluid with the at least one laterally movable blade.

19. The expandable reamer of claim 18, wherein the actuation sleeve is configured to increase a size of the drilling fluid flow path through the expandable reamer by way of allowing drilling fluid communication with at least one alternative drilling fluid flow path subsequent to a restriction element preventing the flow of drilling fluid through the actuation sleeve.

20. The expandable reamer of claim 18, wherein the restriction element comprises a ball sized and configured to engage the actuation sleeve at a seating surface complementarily sized and configured to substantially prevent the flow of drilling fluid therethrough and cause displacement of the actuation sleeve within the expandable reamer to a position that allows communication between drilling fluid and the at least one laterally movable blade.

21. The expandable reamer of claim 1, wherein the at least one laterally movable blade comprises a plurality of laterally movable blades.

22. The expandable reamer of claim 21, wherein a cross-sectional shape of each of the plurality of laterally movable blades in a geometric plane substantially perpendicular to the lateral movement thereof, respectively, comprises at least one of an oval, elliptical, and arcuate shape.

23. The expandable reamer of claim 21, wherein a cross-sectional shape of a portion of each of the plurality of laterally movable blades capable of being positioned laterally outside of the tubular body in a geometric plane substantially perpendicular to the direction of movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

24. The expandable reamer of claim 21, wherein the plurality of laterally movable blades comprises a first plurality of laterally movable blades configured within the tubular body to extend to a first outermost lateral position and a second plurality of laterally movable blades configured within the tubular body to extend to a second outermost lateral position.

25. The expandable reamer of claim 1, wherein the actuation sleeve comprises an actuation sleeve lip configured to engage a wireline tool.

26. The expandable reamer of claim 1, wherein the outermost lateral position of the at least one laterally movable blade is adjustable by way of an adjustable blade spacer element in lateral contact therewith.

27. The expandable reamer of claim 26, wherein the adjustable blade spacer element comprises a replaceable pin or block.

28. The expandable reamer of claim 1, wherein the at least one laterally movable blade comprises a taper at its upper outer longitudinal end.

29. The expandable reamer of claim 21, wherein each of the plurality of laterally movable blades comprises a taper at its upper outer longitudinal end.

30. The expandable reamer of claim 1, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by more than 20%.

31. The expandable reamer of claim 30, wherein the at least one laterally movable blade comprises a plurality of laterally movable blades.

32. The expandable reamer of claim 31, wherein each of the plurality of laterally movable blades is disposed so that its longitudinal extent does not overlap with the longitudinal extent of another of the plurality of laterally movable blades.

33. The expandable reamer of claim 31, wherein the plurality of laterally moveable blades is disposed about the longitudinal axis of the tubular body circumferentially asymmetrically.

34. The expandable reamer of claim 1, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by about 40%.

35. The expandable reamer of claim 1, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by at least 40%. inches.

36. The expandable reamer of claim 25, wherein the plurality of blades is disposed about the longitudinal axis of the tubular body circumferentially asymmetrically.

37. The expandable reamer of claim 1, further comprising a replaceable bearing pad disposed proximate to a lower longitudinal end of the at least one laterally movable blade.

38. The expandable reamer of claim 37, wherein the replaceable bearing pad comprises at least one of hardfacing, diamond, tungsten carbide, and superabrasive materials.

39. The expandable reamer of claim 37, wherein the replaceable bearing pad is affixed to the expandable reamer by way of two or more removable lock rods extending longitudinally through the tubular body thereof.

40. The expandable reamer of claim 1, further comprising at least one laterally movable bearing pad.

41. The expandable reamer of claim 40, wherein a vector sum of lateral cutting forces of the at least one cutting structure carried on the plurality of generally radially and longitudinally extending blades is directed toward the at least one laterally movable bearing pad.

42. The expandable reamer of claim 40, wherein the at least one laterally movable bearing pad includes a first laterally movable bearing pad configured and mounted to the tubular body to extend to an outermost lateral position and a second laterally movable bearing pad configured and mounted to the tubular body to extend to a different outermost lateral position.

43. The expandable reamer of claim 40, wherein the at least one laterally movable bearing pad comprises a plurality of laterally movable bearing pads.

44. The expandable reamer of claim 43, wherein the plurality of laterally movable bearing pads is configured and mounted to the tubular body to extend to a diameter of the a pilot drill bit connected to the expandable reamer downhole therefrom.

45. The expandable reamer of claim 1, further comprising a seal assembly disposed within the expandable reamer between two surfaces configured to move relative to one another comprising a T-shaped seal adjacent at least one backup seal member having a nonplanar wiping surface.

46. The expandable reamer of claim 45, wherein the nonplanar wiping surface comprises a ridged surface.

47. The expandable reamer of claim 46, wherein the T-shaped seal is positioned between two backup seals having nonplanar wiping surfaces comprising ridged surfaces.

48. The expandable reamer of claim 45, wherein the seal assembly is configured to seal a portion of the at least one laterally movable blade.

49. The expandable reamer of claim 45, wherein the seal assembly is configured to seal a portion of the actuation sleeve.

50. The expandable reamer of claim 1, further comprising: a seal assembly disposed within the expandable reamer exposed at least partially to the drilling fluid; and a compensator system configured to equalize pressure within the seal assembly and a pressure of the drilling fluid.

51. The expandable reamer of claim 50, wherein the compensator system is disposed within the at least one laterally movable blade.

52. The expandable reamer of claim 1, further comprising a compensator system configured to supply lubricant and equalize the pressure therein in relation to drilling fluid pressure to a seal within the expandable reamer.

53. The expandable reamer of claim 52, wherein the compensator system is disposed within the at least one laterally movable blade.

54. The expandable reamer of claim 1, wherein the drilling fluid flow path is sized and configured to produce a perceptible drilling fluid pressure response indicating an operational state of the expandable reamer.

55. The expandable reamer of claim 54, wherein the drilling fluid flow path is sized and configured to produce a perceptible drilling fluid pressure response indicating allowance or prevention of drilling fluid communication with the at least one laterally movable blade.

56. The expandable reamer of claim 54, wherein the drilling fluid flow path comprises a port wherein drilling fluid flow therethrough is inhibited in response to a laterally outward movement of the at least one laterally movable blade.

57. The expandable reamer of claim 54, wherein the drilling fluid flow path comprises at least one of a burst disc, shear pin, or pressure accumulator.

58. The expandable reamer of claim 1, wherein the at least one laterally movable blade is retained within the expandable reamer by way of two or more removable lock rods extending longitudinally along and through the tubular body thereof.

59. The expandable reamer of claim 58, wherein the two or more removable lock rods extend longitudinally through a spacing element configured to retain the at least one laterally movable blade within the tubular body of the expandable reamer.

60. The expandable reamer of claim 1, further comprising at least one ovoid structure carried by the at least one laterally movable blade configured to inhibit the at least one cutting structure experiencing excessive or damaging contact.

61. The expandable reamer of claim 60, wherein the at least one cutting structure comprises a plurality of cutting structures and wherein the at least one ovoid structure comprises first and second ovoid structures carried by the at least one laterally movable blade configured to inhibit the plurality of cutting structures experiencing excessive or damaging contact.

62. The expandable reamer of claim 61, wherein the first ovoid structure is disposed at a first longitudinal position on the at least one laterally movable blade and the second ovoid structure is disposed at a second longitudinal position on the at least one laterally movable blade.

63. The expandable reamer of claim 60, wherein the at least one ovoid structure carried by the at least one laterally movable blade comprises at least one of tungsten carbide and a superabrasive material.

64. An expandable reamer for drilling a subterranean formation, comprising: a tubular body having a longitudinal axis a plurality of generally radially and longitudinally extending blades carried by the tubular body, carrying at least one cutting structure thereon, wherein at least one blade of the plurality of blades is laterally movable; at least one blade-biasing element for holding the at least one laterally movable blade at an innermost lateral position with a force, the innermost lateral position corresponding to an initial diameter of the expandable reamer; structure for preventing lateral movement of the at least one laterally movable blade beyond an outermost lateral position, corresponding to an expanded diameter of the expandable reamer; and a separation element substantially separating drilling fluid from another fluid in communication with the at least one laterally movable blade and configured to communicate force or pressure developed by way of the drilling fluid to the another fluid.

65. The expandable reamer of claim 64, wherein the at least one cutting structure comprises a plurality of superabrasive cutters.

66. The expandable reamer of claim 64, wherein a cross-sectional shape of the at least one laterally movable blade in a geometric plane substantially perpendicular to the lateral movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

67. The expandable reamer of claim 64, wherein a cross-sectional shape of a portion of the at least one laterally movable blade capable of being positioned laterally outside of the tubular body in a geometric plane substantially perpendicular to the direction of movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

68. The expandable reamer of claim 64, wherein the separation element comprises one of a piston and a membrane.

69. The expandable reamer of claim 64, wherein the separation element is sized and configured to develop or transmit a selected magnitude of pressure or force upon the at least one laterally movable blade.

70. The expandable reamer of claim 64, further comprising at least one laterally movable bearing pad.

71. The expandable reamer of claim 70, wherein a vector sum of lateral cutting forces of the at least one cutting structure carried on the plurality of generally radially and longitudinally extending blades is directed toward the at least one laterally movable bearing pad.

72. The expandable reamer of claim 64, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by more than 20%.

73. The expandable reamer of claim 72, wherein the at least one laterally movable blade comprises a plurality of laterally movable blades.

74. The expandable reamer of claim 73, wherein each of the plurality of laterally movable blades is disposed so that its longitudinal extent does not overlap with the longitudinal extent of another of the plurality of laterally movable blades.

75. The expandable reamer of claim 64, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by about 40%.

76. The expandable reamer of claim 75, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by at least 40%. inches.

77. The expandable reamer of claim 64, wherein the at least one laterally movable blade is retained within the expandable reamer by way of two or more removable lock rods extending longitudinally along and through the tubular body thereof.

78. The expandable reamer of claim 77, wherein the two or more removable lock rods extend longitudinally through a spacing element configured to retain the at least one laterally movable blade within the tubular body of the expandable reamer.

79. The expandable reamer of claim 64, further comprising at least one ovoid structure carried by the at least one laterally movable blade configured to inhibit the at least one cutting structure experiencing excessive or damaging contact.

80. The expandable reamer of claim 79, wherein the at least one cutting structure comprises a plurality of cutting structures and wherein the at least one ovoid structure comprises first and second ovoid structures carried by the at least one laterally movable blade configured to inhibit the plurality of cutting structures experiencing excessive or damaging contact.

81. The expandable reamer of claim 80, wherein the first ovoid structure is disposed at a first longitudinal position on the at least one laterally movable blade and the second ovoid structure is disposed at a second longitudinal position on the at least one laterally movable blade.

82. The expandable reamer of claim 79, wherein the at least one ovoid structure carried by the at least one laterally movable blade comprises at least one of tungsten carbide and a superabrasive material.

83. An expandable reamer for drilling a subterranean formation, comprising: a tubular body having a longitudinal axis a plurality of generally radially and longitudinally extending blades carried by the tubular body, carrying at least one cutting structure thereon, wherein at least one blade of the plurality of blades is laterally movable; at least one blade-biasing element for holding the at least one laterally movable blade at an innermost lateral position with a force, the innermost lateral position corresponding to an initial diameter of the expandable reamer; structure for preventing lateral movement of the at least one laterally movable blade beyond an outermost lateral position, corresponding to an expanded diameter of the expandable reamer; a drilling fluid path for communicating drilling fluid through the expandable reamer without interaction with the at least one laterally movable blade; and a chamber in communication with the at least one laterally movable blade, substantially sealed from the drilling fluid path and configured for developing pressure therein.

84. The expandable reamer of claim 83, wherein the at least one cutting structure comprises a plurality of superabrasive cutters.

85. The expandable reamer of claim 83, wherein a cross-sectional shape of the at least one laterally movable blade in a geometric plane substantially perpendicular to the lateral movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

86. The expandable reamer of claim 83, wherein a cross-sectional shape of a portion of the at least one laterally movable blade capable of being positioned laterally outside of the tubular body in a geometric plane substantially perpendicular to the direction of movement thereof comprises at least one of an oval, elliptical, and arcuate shape.

87. The expandable reamer of claim 83, wherein the chamber is configured to be operably coupled to and pressurized by way of a downhole pump or turbine.

88. The expandable reamer of claim 83, further comprising at least one laterally movable bearing pad.

89. The expandable reamer of claim 88, wherein a vector sum of lateral cutting forces of the at least one cutting structure carried on the blades of the plurality of generally radially and longitudinally extending blades is directed toward the at least one laterally movable bearing pad.

90. The expandable reamer of claim 83, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by more than 20%.

91. The expandable reamer of claim 84, wherein the at least one laterally movable blade comprises a plurality of laterally movable blades.

92. The expandable reamer of claim 91, wherein each of the plurality of laterally movable blades is disposed so that its longitudinal extent does not overlap with the longitudinal extent of another of the plurality of laterally movable blades.

93. The expandable reamer of claim 83, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by about 40%.

94. The expandable reamer of claim 93, wherein the expanded diameter of the expandable reamer exceeds the initial diameter of the expandable reamer by at least about 40%.

95. The expandable reamer of claim 83, wherein the at least one laterally movable blade is retained within the expandable reamer by way of two or more removable lock rods extending longitudinally along and through the tubular body thereof.

96. The expandable reamer of claim 95, wherein the two or more removable lock rods extend longitudinally through a spacing element configured to retain the at least one laterally movable blade within the tubular body of the expandable reamer.

97. The expandable reamer of claim 83, further comprising at least one ovoid structure carried by the at least one laterally movable blade configured to inhibit the at least one cutting structure experiencing excessive or damaging contact.

98. The expandable reamer of claim 97, wherein the at least one cutting structure comprises a plurality of cutting structures and wherein the at least one ovoid structure comprises first and second ovoid structures carried by the at least one laterally movable blade configured to inhibit the plurality of cutting structures experiencing excessive or damaging contact.

99. The expandable reamer of claim 98, wherein the first ovoid structure is disposed at a first longitudinal position on the at least one laterally movable blade and the second ovoid structure is disposed at a second longitudinal position on the at least one laterally movable blade.

100. The expandable reamer of claim 97, wherein the at least one ovoid structure carried by the at least one laterally movable blade comprises at least one of tungsten carbide and a superabrasive material.

101. A method of reaming a borehole in a subterranean formation, comprising: disposing an expandable reamer apparatus within the subterranean formation, the expandable reamer apparatus including a plurality of blades and having at least one laterally movable blade, each blade of the plurality carrying at least one cutting structure; biasing the at least one laterally movable blade to a laterally innermost position corresponding to an initial diameter of the expandable reamer apparatus; flowing drilling fluid through the expandable reamer apparatus via a drilling fluid flow path while preventing drilling fluid from communicating with the at least one laterally movable blade; allowing drilling fluid to communicate with the at least one laterally movable blade to cause the at least one laterally movable blade to move to an outermost lateral position corresponding to an expanded diameter of the expandable reamer apparatus; and reaming a borehole in the subterranean formation by rotation and displacement of the expandable reamer apparatus within the subterranean formation.

102. The method of claim 101, wherein preventing drilling fluid from communicating with the at least one laterally movable blade comprises positioning an actuation sleeve to prevent drilling fluid communication with the at least one laterally movable blade.

103. The method of claim 102, wherein allowing drilling fluid to communicate with the at least one laterally movable blade comprises positioning an actuation sleeve to allow drilling fluid communication with the at least one laterally movable blade.

104. The method of claim 103, wherein positioning the actuation sleeve to allow or prevent drilling fluid communication with the at least one laterally movable blade comprises positioning the actuation sleeve by way of moving a pin disposed within a groove of a pin guide sleeve.

105. The method of claim 103, further comprising developing a force upon the actuation sleeve by way of flowing drilling fluid through a reduced cross-sectional orifice.

106. The method of claim 102, further comprising: restricting drilling fluid flow through the actuation sleeve.

107. The method of claim, 102, further comprising causing the actuation sleeve to move to a position wherein the longitudinal extent thereof does not coincide with the longitudinal extent of the at least one laterally movable blade.

108. The method of claim 101, further comprising generating a drilling fluid pressure response associated with an operational condition of the expandable reamer apparatus.

109. The method of claim 108, further comprising generating a drilling fluid pressure response by way of relatively rapidly reducing a size of the drilling fluid flow path.

110. The method of claim 108, further comprising identifying the drilling fluid pressure response.

111. The method of claim 101, wherein disposing the expandable reamer apparatus within the subterranean formation comprises disposing the expandable reamer apparatus through a casing section with an inner diameter that is smaller than the expanded diameter of the expandable reamer apparatus.

112. The method of claim 101, further comprising increasing a size of the drilling fluid flow path through the expandable reamer apparatus subsequent to allowing drilling fluid to communicate with the at least one laterally movable blade.

113. A method of reaming a borehole in a subterranean formation, comprising: disposing an expandable reamer apparatus within the subterranean formation, the expandable reamer apparatus including a plurality of blades and having at least one laterally movable blade, each blade of the plurality carrying at least one cutting structure; biasing the at least one laterally movable blade to a laterally innermost position corresponding to an initial diameter of the expandable reamer apparatus; flowing drilling fluid through the expandable reamer apparatus; preventing drilling fluid from communicating with the at least one laterally movable blade; causing the at least one laterally movable blade to move to an outermost lateral position corresponding to an expanded diameter of the expandable reamer apparatus by way of pressurizing another fluid in communication with the at least one laterally movable blade; and reaming a borehole in the subterranean formation by rotation and displacement of the expandable reamer apparatus within the subterranean formation.

114. The method of claim 113, wherein pressurizing the another fluid in communication with the at least one laterally movable blade comprises operating a downhole pump or turbine.

115. A method of reaming a borehole in a subterranean formation, comprising: disposing an expandable reamer apparatus within the subterranean formation, the expandable reamer apparatus including a plurality of blades and having at least one laterally movable blade, each blade of the plurality carrying at least one cutting structure; biasing the at least one laterally movable blade to a laterally innermost position corresponding to an initial diameter of the expandable reamer apparatus; flowing drilling fluid through the expandable reamer apparatus; preventing drilling fluid from communicating with the at least one laterally movable blade by disposing a separation element between the drilling fluid and another fluid in communication with the at least one laterally movable blade; causing the at least one laterally movable blade to move to an outermost lateral position corresponding to an expanded diameter of the expandable reamer apparatus by transmitting force or pressure developed on the separation element by way of the drilling fluid to the at least one laterally movable blade by way of the another fluid in communication therewith; and reaming a borehole in the subterranean formation by rotation and displacement of the expandable reamer apparatus within the subterranean formation.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an expandable reamer apparatus and methods for drilling a subterranean borehole and, more specifically, to enlarging a subterranean borehole beneath a casing or liner. The expandable reamer may comprise a tubular body configured with movable blades that may be displaced radially or laterally outwardly, the movable blades having cutting elements attached thereto.

2. State of the Art

Drill bits for drilling oil, gas, and geothermal wells, and other similar uses typically comprise a solid metal or composite matrix-type metal body having a lower cutting face region and an upper shank region for connection to the bottom hole assembly of a drill string formed of conventional jointed tubular members which are then rotated as a single unit by a rotary table or top drive drilling rig, or by a downhole motor selectively in combination with the surface equipment. Alternatively, rotary drill bits may be attached to a bottom hole assembly, including a downhole motor assembly, which is in turn connected to an essentially continuous tubing, also referred to as coiled, or reeled, tubing wherein the downhole motor assembly rotates the drill bit. The bit body may have one or more internal passages for introducing drilling fluid, or mud, to the cutting face of the drill bit to cool cutters provided thereon and to facilitate formation chip and formation fines removal. The sides of the drill bit typically may include a plurality of radially or laterally extending blades that have an outermost surface of a substantially constant diameter and generally parallel to the central longitudinal axis of the drill bit, commonly known as gage pads. The gage pads generally contact the wall of the borehole being drilled in order to support and provide guidance to the drill bit as it advances along a desired cutting path, or trajectory.

As known within the art, blades provided on a rotary drill bit may be selected to be provided with replaceable cutting elements installed thereon, allowing the cutting elements to engage the formation being drilled and to assist in providing cutting action therealong. Replaceable cutters may also be placed adjacent to the gage area of the rotary drill bit and sometimes on the gage thereof. One type of cutting element, referred to as inserts, compacts, and cutters has been known and used for providing the primary cutting action of rotary drill bits and drilling tools. These cutting elements are typically manufactured by forming a superabrasive layer, or table, upon a sintered tungsten carbide substrate. As an example, a tungsten carbide substrate having a polycrystalline diamond table or cutting face is sintered onto the substrate under high pressure and temperature, typically about 1450.degree. to about 1600.degree. C. and about 50 to about 70 kilobar pressure to form a PDC cutting element or PDC cutter. During this process, a metal sintering aid or catalyst such as cobalt may be premixed with the powdered diamond or swept from the substrate into the diamond to form a bonding matrix at the interface between the diamond and substrate.

Further, in one conventional approach to enlarge a subterranean borehole, it is known to employ both eccentric and bicenter bits to enlarge a borehole below a tight or undersized portion thereof. For example, an eccentric bit includes an extended or enlarged cutting portion which, when the bit is rotated about its axis, produces an enlarged borehole. An example of an eccentric bit is disclosed in U.S. Pat. No. 4,635,738, assigned to the assignee of the present invention. Similarly, a bicenter bit assembly employs two longitudinally superimposed bit sections with laterally offset axes. An example of an exemplary bicenter bit is disclosed in U.S. Pat. No. 5,957,223, also assigned to the assignee of the present invention. The first axis is the center of the pass-through diameter, that is, the diameter of the smallest borehole the bit will pass through. Accordingly, this axis may be referred to as the pass-through axis. The second axis is the axis of the hole cut in the subterranean formation as the bit is rotated and may be referred to as the drilling axis. There is usually a first, lower and smaller diameter pilot section employed to commence the drilling, and rotation of the bit is centered about the drilling axis as the second, upper and larger diameter main bit section engages the formation to enlarge the borehole, the rotational axis of the bit assembly rapidly transitioning from the pass-through axis to the drilling axis when the full diameter, enlarged borehole is drilled.

In another conventional approach to enlarge a subterranean borehole, rather than employing a one-piece drilling structure such as an eccentric bit or a bicenter bit to enlarge a borehole below a constricted or reduced-diameter segment, it is also known to employ an extended bottom hole assembly (extended bicenter assembly) with a pilot drill bit at the distal end thereof and a reamer assembly some distance above. This arrangement permits the use of any standard rotary drill bit type, be it a rock bit or a drag bit, as the pilot bit, and the extended nature of the assembly permits greater flexibility when passing through tight spots in the borehole as well as the opportunity to effectively stabilize the pilot drill bit so that the pilot hole and the following reamer will traverse the path intended for the borehole. This aspect of an extended bottom hole assembly is particularly significant in directional drilling.

The assignee of the present invention has, to this end, designed as reaming structures so-called "reamer wings," which structures generally comprise a tubular body having a fishing neck with a threaded connection at the top thereof and a tong die surface at the bottom thereof, also with a threaded connection. U.S. Pat. Nos. 5,497,842 and 5,495,899, both assigned to the assignee of the present invention, disclose reaming structures including reamer wings. The upper midportion of the reamer wing tool includes one or more longitudinally extending blades projecting generally radially outwardly from the tubular body, the outer edges of the blades carrying PDC cutting elements. The midportion of the reamer wing also may include a stabilizing pad having an arcuate exterior surface having a radius that is the same as or slightly smaller than the radius of the pilot hole on the exterior of the tubular body and longitudinally below the blades. The stabilizer pad is characteristically placed on the opposite side of the body with respect to the reamer blades so that the reamer wing tool will ride on the pad due to the resultant force vector generated by the cutting of the blade or blades as the enlarged borehole is cut. U.S. Pat. No. 5,765,653, assigned to the assignee of the present invention, discloses the use of one or more eccentric stabilizers placed within or above the bottom hole reaming assembly to permit ready passage thereof through the pilot hole or pass-through diameter, while effectively radially stabilizing the assembly during the hole-opening operation thereafter.

Conventional expandable reamers may include blades pivotably or hingedly affixed to a tubular body and actuated by way of a piston disposed therein as disclosed by U.S. Pat. No. 5,402,856 to Warren. In addition, U.S. Pat. No. 6,360,831 to Akesson et al. discloses a conventional borehole opener comprising a body equipped with at least two hole-opening arms having cutting means that may be moved from a position of rest in the body to an active position by way of a face thereof that is directly subjected to the pressure of the drilling fluid flowing through the body. However, the face, being directly exposed to the drilling fluid, may be subjected adversely to erosion or chemical effects caused thereby.

Notwithstanding the prior approaches to drill and/or ream a larger-diameter borehole below a smaller-diameter borehole, the need exists for improved apparatus and methods for doing so. For instance, bicenter and reamer wing assemblies are limited in the sense that the pass-through diameter is nonadjustable and limited by the reaming diameter. Further, conventional reaming assemblies may be subject to damage when passing through a smaller diameter borehole or casing section.

BRIEF SUMMARY OF THE INVENTION

The present invention generally relates to an expandable reamer having movable blades that may be positioned at an initial smaller diameter and expanded to a subsequent diameter to ream and/or drill a larger diameter within a subterranean formation. Such an expandable reamer may be useful for enlarging a borehole within a subterranean formation below a particular depth, since the expandable reamer may be disposed within a borehole of an initial diameter and expanded, rotated, and displaced to form an enlarged borehole therebelow.

In one exemplary embodiment, the expandable reamer of the present invention may include an actuation sleeve whose position may determine deployment of a movable blade therein as described below. For instance, an actuation sleeve may be disposed within the expandable reamer and may have a reduced cross-sectional area aperture or orifice that drilling fluid passes through. Thus, the drilling fluid passing through the expandable reamer and reduced cross-sectional aperture or orifice may cause the actuation sleeve to be displaced by the force generated thereby. Sufficient displacement of the actuation sleeve may allow drilling fluid to communicate through apertures in the displaced actuation sleeve with movable blade sections, the pressure of the drilling fluid forcing the movable blades to expand radially or laterally outwardly. Further, the actuation sleeve may be biased in substantially the opposite direction of the force generated by drilling fluid passing through the reduced cross-sectional area of the actuation sleeve by way of a sleeve-biasing element. Such a sleeve-biasing element may cause the actuation sleeve to be repositioned, in the absence of, or against, the force generated by drilling fluid passing through the reduced cross-sectional orifice, thus preventing drilling fluid from communicating with the movable blades of the expandable reamer. Furthermore, the expandable reamer may include blade-biasing elements configured to return or bias the movable blades radially or laterally inward in the absence of, or against, the pressure of the drilling fluid acting on the movable blades. Moreover, a tapered or-chamfered surface on the upper longitudinal region of each blade may also facilitate return of that movable blade inwardly as the taper or chamfer contacts the borehole wall. Thus, the expandable reamer of the present invention may return to its initial unexpanded condition depending on the position of the actuation sleeve.

In addition, the outermost position of the movable blades, when expanded, may be adjustable. For instance, the expandable reamer of the present invention may be configured so that an adjustable spacer element may be used to determine the outermost radial or lateral position of a movable blade. Such adjustable spacer element may generally comprise a block or pin that may be adjusted or replaced. In addition, in an embodiment including an actuation sleeve that enables the expansion of the movable blades, a sleeve-biasing element, and blade-biasing elements, the sleeve-biasing element may be configured in relation to the blade-biasing elements for the purpose of adjusting the conditions that may cause the movable blades to expand to their outermost radial or lateral positions. For instance, the sleeve-biasing element and reduced cross-sectional orifice may be configured so that a drilling fluid flow rate above a minimum drilling fluid flow rate causes the sleeve to be displaced, thus allowing drilling fluid to communicate with the movable blades. Accordingly, the blade-biasing elements may be configured so that only a drilling fluid flow rate exceeding the drilling fluid flow rate required to open communication between a movable blade and the drilling fluid may cause the movable blades to move radially or laterally outward to their outermost radial or lateral position.

The expandable reamer of the present invention is not limited to actuation sleeves for activating the expansion of the expandable reamer. Collets, shear pins, valves, burst discs, or other mechanisms that enable the expansion of the movable blades of the expandable reamer in relation to an operating condition thereof may be employed. Moreover, a flow restriction element may be disposed within the drill string to actuate the expansion of the expandable reamer. For instance, a ball may be disposed within the drilling fluid, traveling therein, ultimately seating within an actuation sleeve disposed at a first position. Pressure from the drilling fluid may subsequently build to force the ball and actuation sleeve, optionally held in place by way of a shear pin or other friable member, into a second position, thereby actuating the expansion of the expandable reamer. Such a configuration may require that once the movable blades are expanded by the ball, in order to contract the movable blades, the flow is diverted around the seated ball to allow a maximum fluid flow rate through the tool. Thus, the expandable reamer may be configured as a "one shot" tool, which may be reset after actuation.

Further, a pressure-actuated pin guide may be employed to cause the reamer to assume different operational conditions. More specifically, a pin guide may comprise a cylinder with a groove having alternating upwardly sloping and downwardly sloping arcuate paths formed at least partially along the circumference of the cylinder and a pin affixed to an actuation sleeve, the pin disposed within the groove. Alternating opposing forces may be applied to the pin and actuation sleeve assembly to cause the pin to traverse within the groove. One force may be created by way of drilling fluid passing through an orifice and an opposing force may be generated by way of a biasing element, as previously described in relation to an actuation sleeve and associated biasing element. For instance, a relatively high flow rate through the tool may cause the pin to traverse longitudinally downwardly within the groove. Upon the flow rate decreasing, a return force provided by way of the biasing element may cause the pin to traverse longitudinally upwardly within the groove. Further, the longitudinal position of the actuation sleeve may prevent or allow drilling fluid to communicate with the movable blades. Thus, the reamer may be caused to assume different operational conditions as the pin may be caused to traverse within the groove of the pin guide.

Thus, the expandable reamer of the present invention may be configured so that the movable blades expand to an outermost radial or lateral position under selected operating conditions as well as return to an inward radial or lateral position under selected operating conditions. Furthermore, movable blades disposed within the expandable reamer of the present invention may comprise tapered, spiral, or substantially straight longitudinally extending sections extending from the tubular body of the expandable reamer. It also may be advantageous to shape the movable blades so that the longitudinal sides of the movable blades are not straight. For instance, each longitudinal side of the movable blades may comprise an oval, elliptical, or other arcuate shape. Of course, the sides need not be symmetrical, but may be if so desired. Such a configuration may reduce binding of the movable blades as they move radially or laterally inwardly and/or outwardly.

Further, a movable blade of the present invention may be removable and/or replaceable. In one exemplary embodiment, removable lock rods extending through the body of the expandable reamer may be used to affix a spacing element associated with and configured to effectively retain the movable blade within the body of the expandable reamer. Accordingly, removable lock rods extending through the body of the expandable reamer and through the spacing elements may be selectively removed, thus allowing for the spacing element and movable blade to be repaired or replaced. Accordingly, such a configuration may allow for the expandable reamer of the present invention to be easily reconfigured for different diameters or repaired.

PDC cutting elements as described above may be affixed in pockets formed on the movable blades by way of an interference fit or brazing. Alternatively, cutting elements may comprise sintered tungsten carbide inserts ("TCI") without a diamond layer; such a configuration may be useful for drilling out a section of casing, or creating a window within a casing section. Furthermore, blades may be fabricated with impregnated diamond cutting structures as known in the art. Alternatively, an expandable reamer may be configured with rotating roller cones having tungsten carbide inserts, PDC inserts, or steel inserts, as known in the art. Such a configuration may be particularly suited for drilling hard formations.

In addition, structures having an ovoid upper geometry may be disposed