ULTRA-LOW FRICTION COATINGS FOR DRILL STEM ASSEMBLIES

• US 20110220415A1
• Filed: 03/08/2011
• Published: 09/15/2011
• Est. Priority Date: 08/18/2009
• Status: Active Grant

• Current Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Inventors: Ertas, Mehmet Deniz, Rajagopalan, Srinivasan, Ozekcin, Adnan, Zhao, Bo, Bailey, Jeffrey Roberts, Jin, Hyun Woo, Haque, Tabassumul, Walker, Terris Field
• Granted Patent: US 8,561,707 B2
• Time in Patent Office: Days
• US Class Current: 175/57
• CPC Class Codes: C23C 14/024 Deposition of sublayers, e.g. to promote adhesion of the coating C23C14/027 takes precedence
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 30/005 on hard metal substrates
• CPC Class Codes: E21B 17/1085 Wear protectors; Blast joints; Hard facing
• CPC Class Codes: E21B 41/00 Equipment or details not covered by groups E21B15/00 - E21B40/00
• CPC Class Codes: E21B 7/046 horizontal drilling drilling with mechanical conveying means E21B7/003

Abstract

Provided are drill stem assemblies with ultra-low friction coatings for subterraneous drilling operations. In one form, the coated drill stem assemblies for subterraneous rotary drilling operations include a body assembly with an exposed outer surface including a drill string coupled to a bottom hole assembly, a coiled tubing coupled to a bottom hole assembly, or a casing string coupled to a bottom hole assembly and an ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly, hardbanding on at least a portion of the exposed outer surface of the body assembly, an ultra-low friction coating on at least a portion of the hardbanding, wherein the ultra-low friction coating comprises one or more ultra-low friction layers, and one or more buttering layers interposed between the hardbanding and the ultra-low friction coating. The coated drill stem assemblies disclosed herein provide for reduced friction, vibration (stick-slip and torsional), abrasion, and wear during straight hole or directional drilling to allow for improved rates of penetration and enable ultra-extended reach drilling with existing top drives.

Claims

1. A coated drill stem assembly for subterraneous rotary drilling operations comprising:

a body assembly with an exposed outer surface including a drill string coupled to a bottom hole assembly, a coiled tubing coupled to a bottom hole assembly, or a casing string coupled to a bottom hole assembly,

hardbanding on at least a portion of the exposed outer surface of the body assembly,

an ultra-low friction coating on at least a portion of the hardbanding,

wherein the ultra-low friction coating comprises one or more ultra-low friction layers,

and one or more buttering layers interposed between the hardbanding and the ultra-low friction coating.

2. The coated drill stem assembly of claim 1 wherein the hardbanding has a patterned surface.

3. The coated drill stem assembly of claim 2 wherein the patterned hardbanding surface includes recessed and raised features that range from 1 mm to 5 mm in depth.

4. The coated drill stem assembly of claim 3 wherein the recessed features comprise 10% to 90% of the area in the hardbanding region.

5. The coated drill stem assembly of claim 2 wherein the hardbanding has a pattern chosen from lateral grooves or slots, longitudinal grooves or slots, angled grooves or slots, spiral grooves or slots, chevron shaped grooves or slots, recessed dimples, proud dimples, and combinations thereof.

6. The coated drill stem assembly of claim 1 wherein the ultra-low friction coating further comprises one or more buffer layers.

7. The coated drill stem assembly of claim 1 or claim 6 wherein at least one of the layers is graded, or at least one of the interfaces between adjacent layers is graded, or combinations thereof.

8. The coated drill stem assembly of claim 1, wherein the one or more ultra-low friction layers are chosen from an amorphous alloy, an electroless nickel-phosphorous composite, graphite, MoS₂, WS₂, a fullerene based composite, a boride based cermet, a quasicrystalline material, a diamond based material, diamond-like-carbon (DLC), boron nitride, carbon nanotubes, graphene sheets, metallic particles of high aspect ratio, ring-shaped materials including carbon nanorings, oblong particles, and combinations thereof.

9. The coated drill stem assembly of claim 8, wherein the diamond based material is chemical vapor deposited (CVD) diamond or polycrystalline diamond compact (PDC).

10. The coated drill stem assembly of claim 1, wherein at least one ultra-low friction layer is diamond-like-carbon (DLC).

11. The coated drill stem assembly of claim 10, wherein the diamond-like-carbon (DLC) is chosen from ta-C, ta-C:

H, DLCH, PLCH, GLCH, Si-DLC, Ti-DLC, Cr-DLC, N-DLC, O-DLC, B-DLC, Me-DLC, F-DLC, S-DLC and combinations thereof.

12. The coated drill stem assembly of claim 1, wherein the ultra-low friction coating provides a surface energy less than 1 J/m².

13. The coated drill stem assembly of claim 1, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides a hardness greater than 400 VHN.

14. The coated drill stem assembly of claim 1, wherein the coefficient of friction of the coating is less than or equal to 0.15.

15. The coated drill stem assembly of claim 1, wherein the coating provides at least 3 times greater wear resistance than an uncoated drill stem assembly.

16. The coated drill stem assembly of claim 1, wherein the water contact angle of the ultra-low friction coating is greater than 60 degrees.

17. The coated drill stem assembly of claim 1 or 6 wherein the thickness of the ultra-low friction coating ranges from 0.5 microns to 5000 microns.

18. The coated drill stem assembly of claim 1 or 6 wherein the thicknesses of the one or more ultra-low friction, buttering, and buffer layers is between 0.001 and 5000 microns.

19. The coated drill stem assembly of claim 7 wherein the thicknesses of the one or more interfaces are between 0.01 to 10 microns or between 5% to 95% of the thickness of the thinnest adjacent layer.

20. The coated drill stem assembly of claim 6, wherein the one or more buffer layers are chosen from elements, alloys, carbides, nitrides, carbo-nitrides, borides, sulfides, silicides, and oxides of silicon, aluminum, copper, molybdenum, titanium, chromium, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, and combinations thereof.

21. The coated drill stem assembly of claim 1, wherein the hardbanding comprises cermet based materials;

metal matrix composites;

nanocrystalline metallic alloys;

amorphous alloys;

hard metallic alloys;

carbides, nitrides, borides, or oxides of elemental tungsten, titanium, niobium, molybdenum, iron, chromium, and silicon dispersed within a metallic alloy matrix;

or combinations thereof.

22. The coated drill stem assembly of claim 1, wherein the one or more buttering layers comprise a stainless steel, a chrome-based alloy, an iron-based alloy, a cobalt-based alloy, a titanium-based alloy, or a nickel-based alloy, alloys or carbides or nitrides or carbo-nitrides or borides or silicides or sulfides or oxides of the following elements:

silicon, titanium, chromium, aluminum, copper, iron, nickel, cobalt, molybdenum, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, or combinations thereof.

23. The coated drill stem assembly of claim 1, wherein the one or more buttering layers is formed by one or more processes chosen from:

PVD, PACVD, CVD, ion implantation, carburizing, nitriding, boronizing, sulfiding, siliciding, oxidizing, an electrochemical process, an electroless plating process, a thermal spray process, a kinetic spray process, a laser-based process, a friction-stir process, a shot peening process, a laser shock peening process, a welding process, a brazing process, an ultra-fine superpolishing process, a tribochemical polishing process, an electrochemical polishing process, and combinations thereof.

24. The coated drill stem assembly of claim 1, wherein the one or more buttering layers provide an ultra-smooth surface finish of average surface roughness lower than 0.25 micron.

25. The coated drill stem assembly of claim 1 wherein at least one of the buttering layers has a minimum hardness of 400 VHN.

26. A coated drill stem assembly for subterraneous rotary drilling operations comprising:

a body assembly with an exposed outer surface including a drill string coupled to a bottom hole assembly, a coiled tubing coupled to a bottom hole assembly, or a casing string coupled to a bottom hole assembly,

an ultra-low friction coating on at least a portion of the body assembly,

wherein the ultra-low friction coating comprises one or more ultra-low friction layers,

and one or more buttering layers interposed between the body assembly and the ultra-low friction coating,

wherein at least one of the buttering layers has a minimum hardness of 400 VHN.

27. The coated drill stem assembly of claim 26 wherein the ultra-low friction coating further comprises one or more buffer layers.

28. The coated drill stem assembly of claim 26 or claim 27 wherein at least one of the layers is graded, or at least one of the interfaces between adjacent layers is graded, or combinations thereof.

29. The coated drill stem assembly of claim 26, wherein the one or more ultra-low friction layers are chosen from an amorphous alloy, an electroless nickel-phosphorous composite, graphite, MoS₂, WS₂, a fullerene based composite, a boride based cermet, a quasicrystalline material, a diamond based material, diamond-like-carbon (DLC), boron nitride, carbon nanotubes, graphene sheets, metallic particles of high aspect ratio, ring-shaped materials including carbon nanorings, oblong particles, and combinations thereof.

30. The coated drill stem assembly of claim 29, wherein the diamond based material is chemical vapor deposited (CVD) diamond or polycrystalline diamond compact (PDC).

31. The coated drill stem assembly of claim 26, wherein at least one ultra-low friction layer is diamond-like-carbon (DLC).

32. The coated drill stem assembly of claim 31, wherein the diamond-like-carbon (DLC) is chosen from ta-C, ta-C:

H, DLCH, PLCH, GLCH, Si-DLC, Ti-DLC, Cr-DLC, N-DLC, O-DLC, B-DLC, Me-DLC, F-DLC, S-DLC, and combinations thereof.

33. The coated drill stem assembly of claim 26, wherein the ultra-low friction coating provides a surface energy less than 1 J/m².

34. The coated drill stem assembly of claim 26, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides a hardness greater than 400 VHN.

35. The coated drill stem assembly of claim 26, wherein the coefficient of friction of the coating is less than or equal to 0.15.

36. The coated drill stem assembly of claim 26, wherein the coating provides at least 3 times greater wear resistance than an uncoated drill stem assembly.

37. The coated drill stem assembly of claim 26, wherein the water contact angle of the ultra-low friction coating is greater than 60 degrees.

38. The coated drill stem assembly of claim 26 or 27 wherein the thickness of the ultra-low friction coating ranges from 0.5 microns to 5000 microns.

39. The coated drill stem assembly of claim 26 or 27 wherein the thicknesses of the one or more layers are between 0.001 and 5000 microns.

40. The coated drill stem assembly of claim 28 wherein the thicknesses of the one or more interfaces are between 0.01 to 10 microns or between 5% to 95% of the thickness of the thinnest adjacent layer.

41. The coated drill stem assembly of claim 27, wherein the one or more buffer layers are chosen from elements, alloys, carbides, nitrides, carbo-nitrides, borides, sulfides, silicides, and oxides of silicon, aluminum, copper, molybdenum, titanium, chromium, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, or combinations thereof.

42. The coated drill stem assembly of claim 26, wherein one or more exposed outer surfaces further includes hardbanding on at least a portion thereof.

43. The coated drill stem assembly of claim 42, wherein the hardbanding comprises cermet based materials;

metal matrix composites;

nanocrystalline metallic alloys;

amorphous alloys;

hard metallic alloys;

carbides, nitrides, borides, or oxides of elemental tungsten, titanium, niobium, molybdenum, iron, chromium, and silicon dispersed within a metallic alloy matrix;

or combinations thereof.

44. The coated drill stem assembly of claim 42 wherein the hardbanding has a patterned surface.

45. The coated drill stem assembly of claim 44 wherein the patterned hardbanding surface includes recessed and raised features that range from 1 mm to 5 mm in depth.

46. The coated drill stem assembly of claim 45 wherein the recessed features comprise 10% to 90% of the area in the hardbanding region.

47. The coated drill stem assembly of claim 44 wherein the hardbanding has a pattern chosen from:

lateral grooves or slots, longitudinal grooves or slots, angled grooves or slots, spiral grooves or slots, chevron shaped grooves or slots, recessed dimples, proud dimples, and combinations thereof.

48. The coated drill stem assembly of claim 26, wherein the one or more buttering layers comprise a stainless steel, a chrome-based alloy, an iron-based alloy, a cobalt-based alloy, a titanium-based alloy, or a nickel-based alloy, alloys or carbides or nitrides or carbo-nitrides or borides or silicides or sulfides or oxides of the following elements:

silicon, titanium, chromium, aluminum, copper, iron, nickel, cobalt, molybdenum, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, or combinations thereof.

49. The coated drill stem assembly of claim 26, wherein the one or more buttering layers is formed by one or more processes chosen from:

PVD, PACVD, CVD, carburizing, nitriding, boronizing, sulfiding, siliciding, oxidizing, an electrochemical process, an electroless plating process, a thermal spray process, a kinetic spray process, a laser-based process, a friction-stir process, a shot peening process, a laser shock peening process, a welding process, a brazing process, an ultra-fine superpolishing process, a tribochemical polishing process, an electrochemical polishing process, and combinations thereof.

50. The coated drill stem assembly of claim 26, wherein the one or more buttering layers provide an ultra-smooth surface finish of average surface roughness lower than 0.25 micron.

51. A method for reducing friction in a coated drill stem assembly during subterraneous rotary drilling operations comprising:

providing a coated drill stem assembly comprising a body assembly with an exposed outer surface including a drill string coupled to a bottom hole assembly, a coiled tubing coupled to a bottom hole assembly, or a casing string coupled to a bottom hole assembly, hardbanding on at least a portion of the exposed outer surface of the body assembly, and an ultra-low friction coating on at least a portion of the hardbanding, wherein the ultra-low friction coating comprises one or more ultra-low friction layers, and one or more buttering layers interposed between the hardbanding and the ultra-low friction coating, and

utilizing the coated drill stem assembly in subterraneous rotary drilling operations.

52. The method of claim 51 wherein the hardbanding has a patterned surface.

53. The method of claim 52 wherein the patterned hardbanding surface includes recessed and raised features that range from 1 mm to 5 mm in depth.

54. The method of claim 53 wherein the recessed features comprise 10% to 90% of the area in the hardbanding region.

55. The method of claim 52 wherein the hardbanding has a pattern chosen from lateral grooves or slots, longitudinal grooves or slots, angled grooves or slots, spiral grooves or slots, chevron shaped grooves or slots, recessed dimples, proud dimples, and combinations thereof.

56. The method of claim 51 wherein the ultra-low friction coating further comprises one or more buffer layers.

57. The method of claim 51 or claim 56 wherein at least one of the layers is graded, or at least one of the interfaces between adjacent layers is graded, or combinations thereof.

58. The method of claim 51, wherein the one or more ultra-low friction layers are chosen from an amorphous alloy, an electroless nickel-phosphorous composite, graphite, MoS₂, WS₂, a fullerene based composite, a boride based cermet, a quasicrystalline material, a diamond based material, diamond-like-carbon (DLC), boron nitride, carbon nanotubes, graphene sheets, metallic particles of high aspect ratio, ring-shaped materials including carbon nanorings, oblong particles, and combinations thereof.

59. The method of claim 58, wherein the diamond based material is chemical vapor deposited (CVD) diamond or polycrystalline diamond compact (PDC).

60. The method of claim 51, wherein at least one ultra-low friction layer is diamond-like-carbon (DLC).

61. The method of claim 60, wherein the diamond-like-carbon (DLC) is chosen from ta-C, ta-C:

H, DLCH, PLCH, GLCH, Si-DLC, Ti-DLC, Cr-DLC, N-DLC, O-DLC, B-DLC, Me-DLC, F-DLC, S-DLC, and combinations thereof.

62. The method of claim 51, wherein the ultra-low friction coating provides a surface energy less than 1 J/m².

63. The method of claim 51, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides a hardness greater than 400 VHN.

64. The method of claim 51, wherein the coefficient of friction of the coating is less than or equal to 0.15.

65. The method of claim 51, wherein the coating provides at least 3 times greater wear resistance than an uncoated drill stem assembly.

66. The method of claim 51, wherein the water contact angle of the ultra-low friction coating is greater than 60 degrees.

67. The method of claim 51 or 56 wherein the thickness of the ultra-low friction coating ranges from 0.5 microns to 5000 microns.

68. The method of claim 51 or 56 wherein the thicknesses of the one or more ultra-low friction, buttering, and buffer layers is between 0.001 and 5000 microns.

69. The method of claim 57 wherein the thicknesses of the one or more interfaces are between 0.01 to 10 microns or between 5% to 95% of the thickness of the thinnest adjacent layer.

70. The method of claim 56, wherein the one or more buffer layers are chosen from elements, alloys, carbides, nitrides, carbo-nitrides, borides, sulfides, silicides, and oxides of silicon, aluminum, copper, molybdenum, titanium, chromium, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, and combinations thereof.

71. The method of claim 51, wherein the hardbanding comprises cermet based materials;

metal matrix composites;

nanocrystalline metallic alloys;

amorphous alloys;

hard metallic alloys;

carbides, nitrides, borides, or oxides of elemental tungsten, titanium, niobium, molybdenum, iron, chromium, and silicon dispersed within a metallic alloy matrix;

or combinations thereof.

72. The method of claim 51, wherein the one or more buttering layers comprise a stainless steel, a chrome-based alloy, an iron-based alloy, a cobalt-based alloy, a titanium-based alloy, or a nickel-based alloy, alloys or carbides or nitrides or carbo-nitrides or borides or silicides or sulfides or oxides of the following elements:

silicon, titanium, chromium, aluminum, copper, iron, nickel, cobalt, molybdenum, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, or combinations thereof.

73. The method of claim 51, wherein the one or more buttering layers is formed by one or more processes chosen from:

PVD, PACVD, CVD, ion implantation, carburizing, nitriding, boronizing, sulfiding, siliciding, oxidizing, an electrochemical process, an electroless plating process, a thermal spray process, a kinetic spray process, a laser-based process, a friction-stir process, a shot peening process, a laser shock peening process, a welding process, a brazing process, an ultra-fine superpolishing process, a tribochemical polishing process, an electrochemical polishing process, and combinations thereof.

74. The method of claim 51, wherein the one or more buttering layers provide an ultra-smooth surface finish of average surface roughness lower than 0.25 micron.

75. The method of claim 51 wherein at least one of the buttering layers has a minimum hardness of 400 VHN.

76. The method of claim 51, wherein the subterraneous rotary drilling operations are directional including horizontal drilling or extended reach drilling (ERD).

77. The method of claim 76, further including utilizing bent motors or rotary steerable tools during horizontal drilling or extended reach drilling (ERD) to assist with directional control.

78. The method of claim 60, wherein the diamond-like-carbon (DLC) is applied by physical vapor deposition, chemical vapor deposition, or plasma assisted chemical vapor deposition coating techniques.

79. The method of claim 78, wherein the physical vapor deposition coating method is chosen from RF-DC plasma reactive magnetron sputtering, ion beam assisted deposition, cathodic arc deposition and pulsed laser deposition.

80. The method of claim 51, wherein the drill string comprises one or more components chosen from drill pipe, casing, liners, tool joints, transition pipe between the drill string and bottom hole assembly, and combinations thereof.

81. The method of claim 51, wherein the bottom hole assembly comprises one or more components chosen from stabilizers, variable-gauge stabilizers, back reamers, drill collars, flex drill collars, rotary steerable tools, roller reamers, shock subs, mud motors, logging while drilling (LWD) tools, measuring while drilling (MWD) tools, coring tools, under-reamers, hole openers, centralizers, turbines, bent housings, bent motors, drilling jars, accelerator jars, crossover subs, bumper jars, torque reduction subs, float subs, fishing tools, fishing jars, washover pipe, logging tools, survey tool subs, non-magnetic counterparts of any of these components, associated external connections of these components, and combinations thereof.

82. The method of claim 51, wherein the dynamic friction coefficient of the ultra-low friction coating is not lower than 50% of the static friction coefficient of the ultra-low friction coating.

83. The method of claim 51, wherein the dynamic friction coefficient of the ultra-low friction coating is greater than or equal to the static friction coefficient of the ultra-low friction coating.

84. The method of claim 51 wherein the downhole temperature during the subterraneous rotary drilling operations ranges from 20 to 400°

F.

85. The method of claim 51, wherein the drilling rotary speed at the surface during the subterraneous rotary drilling operations ranges from 0 to 200 RPM.

86. The method of claim 51, wherein the drilling mud pressure during the subterraneous rotary drilling operations ranges from 14 psi to 20,000 psi.

87. The method of claim 51, wherein the ultra-low friction coating provides resistance to torsional vibration instability including stick-slip vibration dysfunction of the drill string and bottom hole assembly.

88. The method of claim 51, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides resistance to casing wear greater than or equal to that of an uncoated drill stem assembly.

89. The method of claim 88, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides resistance to casing wear at least 3 times greater than an uncoated drill stem assembly.

90. The method of claim 51, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides substantial reduction in torque by substantially reducing friction and drag during directional or extended reach drilling facilitating drilling deeper and/or longer reach wells with existing top drive capabilities.

91. The method of claim 51, further comprising applying the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly at the drilling rig site in the field or at a local supplier shop to apply new or refurbish worn coatings to extend the life and facilitate continued use of the assembly.

92. The method of claim 60, wherein applying the diamond-like-carbon (DLC) ultra-low friction coating includes evacuating at least a portion of the exposed outer surface of the body assembly through a means for mechanical sealing and pumping down prior to vapor deposition coating.

93. The method of claim 51, wherein the utilizing the coated drill stem assembly with coiled tubing in subterraneous rotary drilling operations provides for underbalanced drilling to reach targeted total depth without the need for drag reducing additives in the mud.

94. The method of claim 51, wherein the utilizing the coated drill stem assembly in subterraneous rotary drilling operations provides for substantial friction and drag reduction without compromising the aggressiveness of a drill bit connected to the coated drill stem assembly to transmit applied torque to rock fragmentation process.

95. The method of claim 51, wherein the corrosion resistance of the ultra-low friction coating is at least equal to the steel used for the body assembly.

96. A method for reducing friction in a coated drill stem assembly during subterraneous rotary drilling operations comprising:

providing a drill stem assembly comprising a body assembly with an exposed outer surface including a drill string coupled to a bottom hole assembly, a coiled tubing coupled to a bottom hole assembly, or a casing string coupled to a bottom hole assembly, an ultra-low friction coating on at least a portion of the body assembly, wherein the ultra-low friction coating comprises one or more ultra-low friction layers, and one or more buttering layers interposed between the body assembly and the ultra-low friction coating. wherein at least one of the buttering layers has a minimum hardness of 400 VHN, and

utilizing the coated drill stem assembly in subterraneous rotary drilling operations.

97. The method of claim 96 wherein the ultra-low friction coating further comprises one or more buffer layers.

98. The method of claim 96 or claim 97 wherein at least one of the layers is graded, or at least one of the interfaces between adjacent layers is graded, or combinations thereof.

99. The method of claim 96, wherein the one or more ultra-low friction layers are chosen from an amorphous alloy, an electroless nickel-phosphorous composite, graphite, MoS₂, WS₂, a fullerene based composite, a boride based cermet, a quasicrystalline material, a diamond based material, diamond-like-carbon (DLC), boron nitride, carbon nanotubes, graphene sheets, metallic particles of high aspect ratio, ring-shaped materials including carbon nanorings, oblong particles, and combinations thereof.

100. The method of claim 99, wherein the diamond based material is chemical vapor deposited (CVD) diamond or polycrystalline diamond compact (PDC).

101. The method of claim 96, wherein at least one ultra-low friction layer is diamond-like-carbon (DLC).

102. The method of claim 101, wherein the diamond-like-carbon (DLC) is chosen from ta-C, ta-C:

H, DLCH, PLCH, GLCH, Si-DLC, Ti-DLC, Cr-DLC, N-DLC, O-DLC, B-DLC, Me-DLC, F-DLC, S-DLC, and combinations thereof.

103. The method of claim 96, wherein the ultra-low friction coating provides a surface energy less than 1 J/m².

104. The method of claim 96, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides a hardness greater than 400 VHN.

105. The method of claim 96, wherein the coefficient of friction of the coating is less than or equal to 0.15.

106. The method of claim 96, wherein the coating provides at least 3 times greater wear resistance than an uncoated drill stem assembly.

107. The method of claim 96, wherein the water contact angle of the ultra-low friction coating is greater than 60 degrees.

108. The method of claim 96 or 97 wherein the thickness of the ultra-low friction coating ranges from 0.5 microns to 5000 microns.

109. The method of claim 96 or 97 wherein the thicknesses of the one or more layers are between 0.001 and 5000 microns.

110. The method of claim 98 wherein the thicknesses of the one or more interfaces are between 0.01 to 10 microns or between 5% to 95% of the thickness of the thinnest adjacent layer.

111. The method of claim 97, wherein the one or more buffer layers are chosen from elements, alloys, carbides, nitrides, carbo-nitrides, borides, sulfides, silicides, and oxides of silicon, aluminum, copper, molybdenum, titanium, chromium, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, or combinations thereof.

112. The method of claim 96, wherein one or more exposed outer surfaces further includes hardbanding on at least a portion thereof.

113. The method of claim 112, wherein the hardbanding comprises cermet based materials;

metal matrix composites;

nanocrystalline metallic alloys;

amorphous alloys;

hard metallic alloys;

carbides, nitrides, borides, or oxides of elemental tungsten, titanium, niobium, molybdenum, iron, chromium, and silicon dispersed within a metallic alloy matrix;

or combinations thereof.

114. The method of claim 112 wherein the hardbanding has a patterned surface.

115. The method of claim 114 wherein the patterned hardbanding surface includes recessed and raised features that range from 1 mm to 5 mm in depth.

116. The method of claim 115 wherein the recessed features comprise 10% to 90% of the area in the hardbanding region.

117. The method of claim 114 wherein the hardbanding has a pattern chosen from:

lateral grooves or slots, longitudinal grooves or slots, angled grooves or slots, spiral grooves or slots, chevron shaped grooves or slots, recessed dimples, proud dimples, and combinations thereof.

118. The method of claim 96, wherein the one or more buttering layers comprise a stainless steel, a chrome-based alloy, an iron-based alloy, a cobalt-based alloy, a titanium-based alloy, or a nickel-based alloy, alloys or carbides or nitrides or carbo-nitrides or borides or silicides or sulfides or oxides of the following elements:

silicon, titanium, chromium, aluminum, copper, iron, nickel, cobalt, molybdenum, tungsten, tantalum, niobium, vanadium, zirconium, hafnium, or combinations thereof.

119. The method of claim 96, wherein the one or more buttering layers is formed by one or more processes chosen from:

PVD, PACVD, CVD, carburizing, nitriding, boronizing, sulfiding, siliciding, oxidizing, an electrochemical process, an electroless plating process, a thermal spray process, a kinetic spray process, a laser-based process, a friction-stir process, a shot peening process, a laser shock peening process, a welding process, a brazing process, an ultra-fine superpolishing process, a tribochemical polishing process, an electrochemical polishing process, and combinations thereof.

120. The method of claim 96, wherein the one or more buttering layers provide an ultra-smooth surface finish of average surface roughness lower than 0.25 micron.

121. The method of claim 96, wherein the subterraneous rotary drilling operations are directional including horizontal drilling or extended reach drilling (ERD).

122. The method of claim 121, further including utilizing bent motors or rotary steerable tools during horizontal drilling or extended reach drilling (ERD) to assist with directional control.

123. The method of claim 101, wherein the diamond-like-carbon (DLC) is applied by physical vapor deposition, chemical vapor deposition, or plasma assisted chemical vapor deposition coating techniques.

124. The method of claim 123, wherein the physical vapor deposition coating method is chosen from RF-DC plasma reactive magnetron sputtering, ion beam assisted deposition, cathodic arc deposition and pulsed laser deposition.

125. The method of claim 96, wherein the drill string comprises one or more components chosen from drill pipe, casing, liners, tool joints, transition pipe between the drill string and bottom hole assembly, and combinations thereof.

126. The method of claim 96, wherein the bottom hole assembly comprises one or more components chosen from stabilizers, variable-gauge stabilizers, back reamers, drill collars, flex drill collars, rotary steerable tools, roller reamers, shock subs, mud motors, logging while drilling (LWD) tools, measuring while drilling (MWD) tools, coring tools, under-reamers, hole openers, centralizers, turbines, bent housings, bent motors, drilling jars, accelerator jars, crossover subs, bumper jars, torque reduction subs, float subs, fishing tools, fishing jars, washover pipe, logging tools, survey tool subs, non-magnetic counterparts of any of these components, associated external connections of these components, and combinations thereof.

127. The method of claim 96, wherein the dynamic friction coefficient of the ultra-low friction coating is not lower than 50% of the static friction coefficient of the ultra-low friction coating.

128. The method of claim 96, wherein the dynamic friction coefficient of the ultra-low friction coating is greater than or equal to the static friction coefficient of the ultra-low friction coating.

129. The method of claim 96, wherein the downhole temperature during the subterraneous rotary drilling operations ranges from 20 to 400°

F.

130. The method of claim 96, wherein the drilling rotary speed at the surface during the subterraneous rotary drilling operations ranges from 0 to 200 RPM.

131. The method of claim 96, wherein the drilling mud pressure during the subterraneous rotary drilling operations ranges from 14 psi to 20,000 psi.

132. The method of claim 96, wherein the ultra-low friction coating provides resistance to torsional vibration instability including stick-slip vibration dysfunction of the drill string and bottom hole assembly.

133. The method of claim 96, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides resistance to casing wear greater than or equal to that of an uncoated drill stem assembly.

134. The method of claim 133, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides resistance to casing wear at least 3 times greater than an uncoated drill stem assembly.

135. The method of claim 96, wherein the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly provides substantial reduction in torque by substantially reducing friction and drag during directional or extended reach drilling facilitating drilling deeper and/or longer reach wells with existing top drive capabilities.

136. The method of claim 96, further comprising applying the ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly at the drilling rig site in the field or at a local supplier shop to apply new or refurbish worn coatings to extend the life and facilitate continued use of the assembly.

137. The method of claim 101, wherein applying the diamond-like-carbon (DLC) ultra-low friction coating includes evacuating at least a portion of the exposed outer surface of the body assembly through a means for mechanical sealing and pumping down prior to vapor deposition coating.

138. The method of claim 96, wherein the utilizing the coated drill stem assembly with coiled tubing in subterraneous rotary drilling operations provides for underbalanced drilling to reach targeted total depth without the need for drag reducing additives in the mud.

139. The method of claim 96, wherein the utilizing the coated drill stem assembly in subterraneous rotary drilling operations provides for substantial friction and drag reduction without compromising the aggressiveness of a drill bit connected to the coated drill stem assembly to transmit applied torque to rock fragmentation process.

140. The method of claim 96, wherein the corrosion resistance of the ultra-low friction coating is at least equal to the steel used for the body assembly.