Steerable drilling system and method

• US 6,581,699 B1
• Filed: 08/21/1999
• Issued: 06/24/2003
• Est. Priority Date: 12/21/1998
• Status: Expired due to Term

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Gleitman, Daniel D., Hardin, John R. Jr., Chen, Chen-Kang D., Rao, M. Vikram, Walker, Colin, Boulton, Roger, Gaynor, Thomas M.
• Primary Examiner(s): Will, Thomas B.
• Assistant Examiner(s): Markovich, Kristine
• Application Number:
  US09/378,023
• Time in Patent Office: 1,403 Days
• Field of Search: 175/50, 175/61, 175/62, 175/73, 175/75, 175/45, 175/26, 175/40, 175/27
• US Class Current: 175/61
• CPC Class Codes: E21B 47/013 Devices specially adapted for supporting measuring instruments on drill bits
• CPC Class Codes: E21B 7/067 with means for locking sections of a pipe or of a guide for a shaft in angular relation, e.g. adjustable bent sub
• CPC Class Codes: E21B 7/068 drilled by a down-hole drilling motor down-hole drives per se E21B4/00, E21B7/067 takes precedence

Abstract

A bottom hole assembly 10 for drilling a deviated borehole includes a positive displacement motor (PDM) 12 or a rotary steerable device (RSD) 110 having a substantially uniform diameter motor housing outer surface without stabilizers extending radially therefrom. In a PDM application, the motor housing 14 may have a fixed bend therein between an upper power section 16 and a lower bearing section 18. The long gauge bit 20 powered by the motor 10 may have a bit face 22 with cutters 28 thereon and a gauge section 24 having a uniform diameter cylindrical surface 26. The gauge section 24 preferably has an axial length at least 75% of the bit diameter. The axial spacing between the bit face and the bend of the motor housing preferably is less than twelve times the bit diameter. According to the method of the present invention, the bit may be rotated at a speed of less than 350 rpm by the PDM and/or rotation of the RSD from the surface.

Claims

1. A bottom hole assembly for drilling a deviated borehole the bottom hole assembly comprising:

a rotary shaft having a lower central axis offset at a selected bend angle from an upper central axis by a bend;

a housing having a substantially uniform diameter housing outer surface extending from above the bend to a lowermost end of the housing and without a stabilizer thereon, the housing containing at least a portion of the upper axis of the rotary shaft;

a bit powered by the rotating shaft, the bit having a bit face defining a bit diameter;

a gauge section rotatably fixed to the bit and having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter; and

the gauge section having a total gauge length of at least 75% of the bit diameter and a portion of the total gauge length which has the substantially uniform diameter cylindrical surface is at least 50% of the total gauge length.

2. The bottom hole assembly as defined in claim 1, wherein an axial spacing along the lower central axis between the bend and the bit face is less than twelve times the bit diameter.

3. The bottom hole assembly as defined in claim 2, wherein the bit is a long gauge bit supporting the gauge section.

4. The bottom hole assembly as defined in claim 2, wherein the bit is a conventional bit with a piggyback stabilizer providing at least a portion of the gauge section.

5. The bottom hole assembly as defined in claim 2, further comprising:

the rotary shaft having a pin connection as its lowermost end; and

the gauge section having a box connection at its upper end for mating interconnection with the pin connection to reduce the axial spacing between the bend and the bit.

6. The bottom hole assembly as defined in claim 1, wherein the housing comprises a rotary steerable housing and the rotary shaft contained within the housing is rotatable with respect to the housing from the surface.

7. The bottom hole assembly as defined in claim 6, wherein an axial spacing between the bend and the bit face is less than eight times the bit diameter.

8. The bottom hole assembly as defined in claim 6, wherein the bend is less than about 0.6°

.

9. The bottom hole assembly as defined in claim 6, wherein the rotary steerable housing is suspended in the wellbore from coiled tubing.

10. The bottom hole assembly defined in claim 1, wherein the housing comprises a motor housing.

11. The bottom hole assembly as defined in claim 10, wherein the bottom hole assembly is supported in the wellbore by drill pipe, such that the motor housing is rotated with the drill pipe to form a straight section of the deviated borehole.

12. The bottom hole assembly as defined in claim 11, further comprising:

a drill collar assembly above the motor housing, the drill collar assembly having an axial length less than 200 feet.

13. The bottom hole assembly as defined in claim 10, wherein the motor housing is suspended in the well from coiled tubing.

14. The bottom hole assembly defined in claim 10, wherein the axial spacing between the bit face and the bend of the motor housing is less than ten times the bit diameter.

15. The bottom hole assembly as defined in claim 1, wherein the bit has a total gauge length of at least 90% of the bit diameter.

16. The bottom hole assembly as defined in claim 1, further comprising:

one or more downhole sensors positioned substantially along the total gauge length for sensing one or more desired borehole parameters.

17. The bottom hole assembly as defined in claim 16, wherein the one or more sensors are supported on a piggyback stabilizer rotatably fixed to the bit and providing at least a portion of the gauge section.

18. The bottom hole assembly as defined in claim 1, further comprising:

the rotary shaft having a pin connection at its lowermost end; and

the bit is a long gauge bit with the gauge section thereon and having a box connection at its upper end for mating interconnection with the pin connection to reduce an axial spacing between the bend and the bit face of the long gauge bit.

19. A method of drilling a deviated borehole utilizing a bottom hole assembly including a rotary shaft having a lower central axis offset at a selected bend angle from an upper central axis by a bend, the bottom hole assembly further including a bit rotated by the rotary shaft and having a bit face defining a bit diameter, the method comprising:

(a) providing a housing having a substantially uniform diameter outer surface surrounding the rotary shaft upper axis, the substantially uniform of diameter outer surface extending from above a bend defining the bend angle to a lowermost end of the housing and without a stabilizer thereon;

(b) providing a gauge section rotatable fixed to the bit and having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a total gauge length of at least 75% of the bit diameter, and a portion of the total gauge length which has the substantially uniform diameter cylindrical surface is at least 50% of the total gauge length; and

(c) rotating the bit at a speed of less than 350 rpm to form a curved section of the deviated borehole.

20. The method as defined in claim 19, further comprising:

axially spacing the bend from the bit face less than twelve times the bit diameter.

21. The method as defined in claim 19, further comprising:

the housing is a motor housing; and

(d) rotating the motor housing within the borehole to rotate the bit to form a straight section of the deviated borehole.

22. The method as defined in claim 21, wherein steps (c) and (d) are each repeated one or more times, and step (d) is performed between two step (c) operations.

23. The method as defined in claim 19, wherein at least a portion of the gauge section is supported on a piggyback stabilizer.

24. The method as defined in claim 19, further comprising:

suspending the housing in the wellbore from coiled tubing.

25. The method as defined in claim 19, further comprising:

positioning one or more downhole sensors substantially along the total gauge length for sensing one or more desired borehole parameters.

26. The method as defined in claim 25, wherein the one or more downhole sensors are positioned substantially along the gauge section of a piggyback stabilizer.

27. The method as defined in claim 19, further comprising:

controlling weight on the bit such that the bit face exerts less than about 200 pounds axial force per square inch of bit face cross-sectional area.

28. A bottom hole assembly for drilling a deviated borehole, the bottom hole assembly comprising:

a rotary shaft having a lower central axis offset at a selected bend angle from an upper central axis by a bend;

a housing having a substantially uniform diameter housing outer surface, the housing containing at least a portion of the upper axis of the rotary shaft;

a bit powered by the rotating shaft, the bit having a bit face defining a bit diameter;

a piggyback stabilizer positioned above the bit and having a stabilizer gauge section;

the stabilizer gauge section having a substantially uniform diameter cylindrical surface spaced above the bit face, the bit and stabilizer gauge section together having a total gauge length of at least 75% of the bit diameter and a portion of the total gauge length which has the substantially uniform diameter cylindrical surface is at least 50% of the total gauge length; and

one or more sensors spaced substantially along the stabilizer gauge section for sensing selected parameters while drilling.

29. The bottom hole assembly as defined in claim 28, wherein an axial spacing between the bend and the bit face is less than twelve times the bit diameter.

30. The bottom hole assembly as defined in claim 29, wherein the one or more sensors include a vibration sensor.

31. The bottom hole assembly as defined in claim 29, wherein the one or more sensors include an RPM sensor for sensing the rotational speed of the rotary shaft.

32. The bottom hole assembly as defined in claim 29, further comprising:

the rotary shaft being rotated by a downhole motor;

an MWD sub located above the motor; and

a telemetry system for communicating data from the one or more sensors in real time to the MWD sub, the telemetry system being selected from an acoustic system and an electromagnetic system.

33. The bottom hole assembly as defined in claim 29, further comprising;

a data storage unit supported substantially along the total gauge length of the bit and gauge section for storing data from the one or more sensors.

34. The bottom hole assembly as defined in claim 29, wherein the one or more sensors sense indications relating to drilling and are provided to the drilling operator in real time.

35. A bottom hole assembly for drilling a deviated borehole, the bottom hole assembly comprising:

a shaft rotated from the surface and having a lower central axis offset at a selected bend angle from an upper central axis by a bend;

a housing containing at least a portion of the upper central axis of the rotary shaft;

a gauge section powered by the rotating shaft, a bit having a bit face defining a bit diameter;

the gauge section rotatably fixed to the bit and having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a total gauge length of at least 75% of the bit diameter and a portion of the total gauge length which has the substantially uniform diameter cylindrical surface is at least 50% of the total gauge length;

the shaft having a pin connection at its lowermost end; and

the gauge section having a box connection at its upper end for mating interconnection with the pin connection.

36. The bottom hole assembly as defined in claim 35, wherein the bit is a long gauge bit supporting the gauge section.

37. The bottom hole assembly as defined in claim 35, wherein the bit includes a piggyback stabilizer supports at least a portion of the total gauge length.

38. The bottom hole assembly as defined in claim 35, wherein the axial spacing between the bend and the bit face is less than eight times the bit diameter and the bend is less than about 0.6°

.

39. The bottom hole assembly as defined in claim 35, wherein the total gauge length is at least 90% of the bit diameter.

40. The bottom hole assembly as defined in claim 35, further comprising:

one or more downhole sensors positioned substantially along the gauge section of the bit for sensing a desired borehole parameter.

41. The bottom hole assembly as defined in claim 35, further comprising:

one or more downhole sensors housed substantially within the gauge section of the long gauge bit for sensing a desired borehole parameter.

42. The bottom hole assembly as defined in claim 35, wherein an axial spacing between the bend and the bit face being less than ten times the bit diameter.

43. A bottom hole assembly for drilling a deviated borehole, the bottom hole assembly comprising:

a positive displacement motor driven by pumping fluid through a motor stator to rotate a motor rotor, the motor including a rotary motor output shaft having a lower central axis offset at a selected bend angle from a motor rotor central axis by a bend;

a rotary bit powered by the rotary motor output shaft, the bit having a bit face defining a bit diameter;

a gauge section rotatably fixed to the rotary bit, the gauge section having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a gauge length of at least 75% of the bit diameter; and

an axial spacing between the bend and the bit face is less than twelve times the bit diameter.

44. The bottom hole assembly as defined in claim 43, wherein a lower first point of contact between the bottom hole assembly and the borehole is at the bit face, a next higher second point of contact between the bottom hole assembly and the borehole is at the gauge section, and a next higher third point of contact between the bottom hole assembly and the borehole is above the bend.

45. The bottom hole assembly as defined in claim 43, wherein the motor stator has a substantially uniform diameter outer surface extending from above the bend to a lowermost end of the motor stator.

46. The bottom hole assembly as defined in claim 43, wherein the axial spacing between the bend and the bit face is less than ten times the bit diameter.

47. The bottom hole assembly, as defined in claim 43, wherein a portion of the gauge length which is substantially gauge is at least 50% of the gauge length.

48. The bottom hole assembly as defined in claim 43, wherein the gauge length of the gauge section is at least 90% of the bit diameter.

49. The bottom hole assembly as defined in claim 43, wherein a piggyback stabilizer rotatably fixed to the bit provides at least a portion of the gauge section.

50. The bottom hole assembly as defined in claim 43, further comprising:

one or more downhole sensors positioned substantially along the gauge section for sensing one or more desired borehole parameters.

51. The bottom hole assembly as defined in claim 43, further comprising:

a drill collar assembly above the motor stator, the drill collar assembly having an axial length of at least 200 feet.

52. A method of drilling a deviated borehole utilizing a bottom hole assembly including a positive displacement motor driven by pumping fluid through a motor stator to rotate a motor rotor, the motor including a rotary motor output shaft having a lower central axis offset at a selected bend angle from a motor rotor central axis by a bend, the bottom hole assembly further including a bit rotated by the rotary motor output shaft and having a bit face defining a bit diameter, the method comprising:

(a) providing a gauge section rotatably affixed to the bit, the gauge section having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a gauge length of at least 75% of the bit diameter;

(b) axially spacing the bend from the bit face less than twelve times the bit diameter; and

(c) powering the positive displacement motor to drill the borehole.

53. The method as defined in claim 52, wherein the axial spacing between the bend and the bit face is at least ten times the bit diameter.

54. The method as defined in claim 52, comprising:

contacting the bottom hole assembly and the borehole at a lower first point of contact at the bit face;

contacting the bottom hole assembly and the borehole at a next higher second point of contact at the gauge section; and

contacting the bottom hole assembly and the borehole at a next higher third point of contact spaced above the bend.

55. The method as defined in claim 52, further comprising:

positioning one or more sensors substantially along the gauge section for sensing one or more desired borehole parameters; and

altering drilling of the borehole in response to the sensed parameters.

56. The method as defined in claim 52, further comprising:

rotating the motor stator within the borehole to form a straight section of the borehole.

57. The method as defined in claim 52, further comprising:

rotating fixing a piggyback stabilizer to the bit, the piggyback stabilizer including at least a portion of the gauge section thereon.

58. The method as defined in claim 52, further comprising:

providing a drill collar assembly above the motor stator, the drill collar assembly having an axial length of less than 200 feet.

59. A bottom hole assembly for drilling a deviated borehole, the bottom hole assembly comprising:

a housing for a rotary output shaft having a lower central axis offset at a selected bend angle from a rotor central axis by a bend;

a rotary bit powered by the rotary output shaft, the bit having a bit face defining a bit diameter;

a gauge section rotatably fixed to the rotary bit, the gauge section having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a gauge length of at least 75% of the bit diameter;

an axial spacing between the bend and the bit face is less than twelve times the bit diameter;

the rotary output shaft having a pin connection at its lowermost end; and

the gauge section having a box connection at its upper end for mating engagement with the pin connection.

60. The bottom hole assembly as defined in claim 59, wherein a lower first point of contact between the bottom hole assembly and the borehole is at the bit face, a next higher second point of contact between the bottom hole assembly and the borehole is at the gauge section, and a next higher third point of contact between the bottom hole assembly and the borehole is above the bend.

61. The bottom hole assembly as defined in claim 59, wherein the axial spacing between the bend and the bit face is less than ten times the bit diameter.

62. The bottom hole assembly as defined in claim 59, wherein the housing is a positive displacement motor housing driven by pumping fluid through the housing for rotating the rotary output shaft.

63. The bottom hole assembly as defined in claim 59, wherein the gauge length of the gauge section is at least 90% of the bit diameter.

64. The bottom hole assembly as defined in claim 59, wherein a piggyback stabilizer rotatably fixed to the bit provides at least a portion of the gauge section.

65. The bottom hole assembly as defined in claim 59, wherein the housing has a substantially uniform diameter outer surface extending from above the bend to a lowermost end of the housing.

66. The bottom hole assembly as defined in claim 59, wherein the housing from above the bend to a lowermost end of the housing is without a stabilizer thereon.

67. The bottom hole assembly as defined in claim 59, wherein a portion of the gauge length which is substantially gauge is at least 50% of the gauge length.

68. The bottom hole assembly as defined in claim 59, further comprising:

one or more downhole sensors positioned substantially along the gauge section for sensing one or more desired borehole parameters.

69. A bottom hole assembly for drilling a deviated borehole, the bottom hole assembly comprising:

a rotary shaft having a lower central axis offset at a selected bend angle from an upper central axis by a bend;

a housing extending from above the bend to below the bend and enclosing at least a portion of the rotary shaft;

a rotary bit powered by the rotary shaft, the bit having a bit face defining a bit diameter;

a gauge section rotatably fixed to the rotary bit, the gauge section having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a gauge length of at least 75% of the bit diameter; and

an axial spacing between the bend and the bit face is less than twelve times the bit diameter.

70. The bottom hole assembly as defined in claim 69, wherein a lower first point of contact between the bottom hole assembly and the borehole is at the bit face, a next higher second point of contact between the bottom hole assembly and the borehole is at the gauge section, and a next higher third point of contact between the bottom hole assembly and the borehole is above the bend.

71. The bottom hole assembly as defined in claim 69, wherein the axial spacing between the bend and the bit face is less than ten times the bit diameter.

72. The bottom hole assembly as defined in claim 69, wherein the axial spacing between the bend and the bit face is less than eight times the bit diameter.

73. The bottom hole assembly as defined in claim 69, wherein the housing has a substantially uniform diameter outer surface extending from above the bend to a lowermost end of the motor stator.

74. The bottom hole assembly as defined in claim 69, wherein the gauge length of the gauge section is at least 90% of the bit diameter.

75. The bottom hole assembly as defined in claim 69, further comprising:

the housing comprises a rotary steerable housing and the rotary shaft enclosed within the housing is rotated with respect to the housing from the surface.

76. The bottom hole assembly as defined in claim 69, wherein the housing includes a motor stator and the rotary shaft includes a motor stator driving by pumping fluid through the motor stator.

77. The bottom hole assembly as defined in claim 69, further comprising:

one or more downhole sensors positioned substantially along the gauge section for sensing one or more desired borehole parameters.

78. The bottom hole assembly as defined in claim 69, wherein the one or more sensors include a vibration sensor.

79. The bottom hole assembly as defined in claim 77, wherein the one or more sensors include an RPM sensor for sensing the rotational speed of the rotary shaft.

80. The bottom hole assembly as defined in claim 77, further comprising:

a telemetry system for communicating data from the one or more sensors in real time to the surface, the telemetry system being selected from an acoustic system and an electromagnetic system.

81. The bottom hole assembly as defined in claim 77, further comprising:

a data storage unit supported along the gauge section for storing data from the one or more sensors.

82. The bottom hole assembly as defined in claim 69, wherein a piggyback stabilizer rotatably fixed to the bit provides at least a portion of the gauge section.

83. The bottom hole assembly as defined in claim 69, wherein the rotary shaft has a pin connection as its lowermost end, the bit having a box connection at its upper end for mating interconnection with the pin connection to reduce an axial spacing between the bend and the bit.

84. The bottom hole assembly as defined in claim 69, further comprising:

a drill collar assembly above the motor stator, the drill collar assembly having an axial length of at least 200 feet.

85. The bottom hole assembly as defined in claim 69, wherein the gauge length which is substantially gauge is at least 50% of the gauge length.

86. The bottom hole assembly as defined in claim 69, wherein the housing is slick without a stabilizer thereon.

87. A method of drilling a deviated borehole utilizing a bottom hole assembly including a rotary shaft having a lower central axis offset at a selected bend angle from an upper central axis by a bend, the bottom hole assembly further including a bit rotated by the rotary shaft and having a bit face defining a bit diameter, the method comprising:

providing a housing for the rotary shaft;

providing an axial spacing between the bend and the bit face of the less than twelve times the bit diameter;

providing a gauge section rotatable fixed to the bit and having a substantially uniform diameter cylindrical surface spaced above the bit face which is substantially equal to the bit diameter, the gauge section having a total gauge length of at least 75% of the bit diameter; and

rotating the bit at a speed of less than 350 rpm to form a curved section of the deviated borehole.

88. The method as defined in claim 87, further comprising:

positioning one or more downhole sensors substantially along the total gauge length for sensing one or more borehole parameters; and

altering drilling in response to the sensed parameters.

89. The method as defined in claim 87, further comprising:

providing a lower first point of contact between the bottom hole assembly and the borehole at the bit face;

providing a second higher point of contact between the bottom hole assembly and the borehole at the gauge section; and

providing a next higher through point of contact between the bottom hole assembly and the borehole above the bend.

90. The method as defined in claim 87, further comprising:

providing a substantially uniform diameter outer surface on the housing extending from above the bend to a lowermost end of the housing.

91. The method as defined in claim 87, wherein the gauge length of the gauge section is at least 90% of the bit diameter.

92. The method as defined in claim 87, wherein at least a portion of the gauge section is provided on a piggyback stabilizer rotatably fixed to the bit.

93. The method as defined in claim 87, further comprising:

providing a drill collar assembly above the housing, the drill collar assembly having an axial length of at least two hundred feet.

94. The method as defined in claim 87, wherein a portion of the gauge length which is substantially gauge is at least 50% of the gauge length.

95. The method as defined in claim 87, further comprising:

rotating the motor stator within the borehole to form a straight section of the borehole.

96. The method as defined in claim 87, further comprising:

controlling weight on the bit so that the bit face exerts less than about 200 lbs axial force per square inch of bit face cross-sectional area.