Apparatus and method for high temperature drilling operations

Abstract

An apparatus ( 50 ) for drilling a wellbore that transverses a subterranean hydrocarbon bearing formation. The apparatus ( 50 ) includes a drill string ( 52 ) having an inner fluid passageway ( 66 ). A drill bit ( 64 ) is disposed at a distal end of the drill string ( 52 ) and is operable to rotate relative to at least a portion of the drill string ( 52 ). A fluid motor ( 54 ) is disposed within the drill string ( 52 ) and is operable to rotate the drill bit ( 64 ) in response to a circulating fluid received via the inner fluid passageway ( 66 ) of the drill string ( 52 ). The fluid motor ( 54 ) has a stator ( 68 ) with (n) lobes and a rotor ( 70 ) with (n−1) lobes. The stator ( 68 ) includes an inner surface formed from a first material and the rotor ( 70 ) includes an outer surface formed from a second material that is dissimilar to the first material.

1 . An apparatus for drilling a wellbore that transverses a subterranean formation, the apparatus comprising:
 a drill string having an inner fluid passageway;   a drill bit disposed at a distal end of the drill string and operable to rotate relative to at least a portion of the drill string; and   a fluid motor disposed within the drill string and operable to rotate the drill bit in response to a circulating fluid received via the inner fluid passageway of the drill string, the fluid motor having a stator with (n) lobes and a rotor with (n−1) lobes, the stator having an inner surface formed from a first metal, the rotor having an outer surface formed from a second metal that is dissimilar to the first metal, thereby providing metal-to-metal contact during operation.   
   
   
       2 . The apparatus as recited in  claim 1  wherein the stator further comprises a stator housing and a stator sleeve, the stator housing and a stator sleeve formed from dissimilar metals. 
   
   
       3 . The apparatus as recited in  claim 1  wherein the stator further comprises a stator housing and a stator coating, the stator housing and the stator coating formed from dissimilar metals. 
   
   
       4 . The apparatus as recited in  claim 1  wherein the stator further comprises a stator housing, a stator sleeve and a stator coating, the stator housing and the stator sleeve formed from metal dissimilar to the stator coating. 
   
   
       5 . The apparatus as recited in  claim 1  wherein the rotor further comprises a solid metal rotor. 
   
   
       6 . The apparatus as recited in  claim 1  wherein the rotor further comprises rotor bore operable to provide a bypass for a portion of the circulating fluid. 
   
   
       7 . The apparatus as recited in  claim 1  wherein the rotor further comprises a rotor mandrel and a rotor sleeve, the rotor mandrel and the rotor sleeve formed from dissimilar metals. 
   
   
       8 . The apparatus as recited in  claim 1  wherein the rotor further comprises a rotor member and a rotor coating, the rotor member and the rotor coating formed from dissimilar metals. 
   
   
       9 . The apparatus as recited in  claim 1  wherein the rotor further comprises a rotor mandrel, a rotor sleeve and a rotor coating, the rotor mandrel and the rotor sleeve formed from metal dissimilar to the metal of the rotor coating. 
   
   
       10 . A fluid motor for use in drilling a wellbore that transverses a subterranean formation to impart rotary motion to a drill bit in response to a circulating fluid, the fluid motor comprising:
 a helical stator with (n) lobes, the stator having an inner surface formed from a first metal; and   a helical rotor with (n−1) lobes, the rotor having an outer surface formed from a second metal that is dissimilar to the first metal, thereby providing metal-to-metal contact during operation.   
   
   
       11 . The fluid motor as recited in  claim 10  wherein the stator further comprises a stator housing and a stator sleeve, the stator housing and a stator sleeve formed from dissimilar metals. 
   
   
       12 . The fluid motor as recited in  claim 10  wherein the stator further comprises a stator housing and a stator coating, the stator housing and the stator coating formed from dissimilar metals. 
   
   
       13 . The fluid motor as recited in  claim 10  wherein the stator further comprises a stator housing, a stator sleeve and a stator coating, the stator housing and the stator sleeve formed from metal dissimilar to the stator coating. 
   
   
       14 . The fluid motor as recited in  claim 10  wherein the rotor further comprises a solid metal rotor. 
   
   
       15 . The fluid motor as recited in  claim 10  wherein the rotor further comprises rotor bore operable to provide a bypass for a portion of the circulating fluid. 
   
   
       16 . The fluid motor as recited in  claim 10  wherein the rotor further comprises a rotor mandrel and a rotor sleeve, the rotor mandrel and the rotor sleeve formed from dissimilar metals. 
   
   
       17 . The fluid motor as recited in  claim 10  wherein the rotor further comprises a rotor member and a rotor coating, the rotor member and the rotor coating formed from dissimilar metals. 
   
   
       18 . The fluid motor as recited in  claim 10  wherein the rotor further comprises a rotor mandrel, a rotor sleeve and a rotor coating, the rotor mandrel and the rotor sleeve formed from metal dissimilar to the metal of the rotor coating. 
   
   
       19 . A method for drilling a wellbore that transverses a subterranean formation, the method comprising:
 disposing a drill bit on a distal end of a drill string having an inner fluid passageway;   positioning a fluid motor within the drill string, the fluid motor having a stator with (n) lobes and a rotor with (n−1) lobes, the stator having an inner surface formed from a first metal, the rotor having an outer surface formed from a second metal that is dissimilar to the first metal, providing metal-to-metal contact during operation;   pumping a circulating fluid through the inner fluid passageway of the drill string and the fluid motor;   converting the hydraulic energy of the circulating fluid to mechanical energy in the fluid motor causing rotation of the rotor; and   rotating the drill bit in response to the rotation of the rotor.   
   
   
       20 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a stator having a stator housing and a stator sleeve, the stator housing and a stator sleeve formed from dissimilar metals. 
   
   
       21 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a stator having stator housing and a stator coating, the stator housing and the stator coating formed from dissimilar metals. 
   
   
       22 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a stator having stator housing, a stator sleeve and a stator coating, the stator housing and the stator sleeve formed from metal dissimilar to the stator coating. 
   
   
       23 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a solid metal rotor. 
   
   
       24 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a rotor having a rotor bore operable to provide a bypass for a portion of the circulating fluid. 
   
   
       25 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a rotor having a rotor mandrel and a rotor sleeve, the rotor mandrel and the rotor sleeve formed from dissimilar metals. 
   
   
       26 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a rotor having a rotor member and a rotor coating, the rotor member and the rotor coating formed from dissimilar metals. 
   
   
       27 . The method as recited in  claim 19  wherein positioning a fluid motor within the drill string further comprises positioning a fluid motor within the drill string including a rotor having a rotor mandrel, a rotor sleeve and a rotor coating, the rotor mandrel and the rotor sleeve formed from metal dissimilar to the metal of the rotor coating. 
   
   
       28 . A fluid motor for use in drilling a wellbore that transverses a subterranean formation to impart rotary motion to a drill bit in response to a circulating fluid, the fluid motor comprising:
 a helical stator with (n) lobes, the stator having an inner surface; and   a helical rotor with (n−1) lobes, the rotor having a rotor mandrel and a rotor sleeve, the rotor sleeve positioned exteriorly of at least a portion of the rotor mandrel, the rotor having an outer surface that contacts the inner surface of the stator as the rotor rotates and precesses within the stator.   
   
   
       29 . The fluid motor as recited in  claim 28  wherein the rotor mandrel and the rotor sleeve are formed from dissimilar materials. 
   
   
       30 . The fluid motor as recited in  claim 29  wherein the rotor mandrel is formed from a metal and the rotor sleeve is formed from a nanocomposite material. 
   
   
       31 . The fluid motor as recited in  claim 29  wherein the rotor mandrel and a rotor sleeve are formed from dissimilar metals. 
   
   
       32 . The fluid motor as recited in  claim 28  wherein the rotor further comprises a rotor coating, the rotor coating forming on the outer surface of the rotor sleeve. 
   
   
       33 . The fluid motor as recited in  claim 32  wherein the rotor mandrel and the rotor sleeve are formed from material that is dissimilar to the rotor coating. 
   
   
       34 . The fluid motor as recited in  claim 33  wherein the rotor mandrel and the rotor sleeve are formed from metal and the rotor coating is formed from a nanocomposite material. 
   
   
       35 . The fluid motor as recited in  claim 33  wherein the rotor mandrel and a rotor sleeve are formed from metal dissimilar to the rotor coating. 
   
   
       36 . The fluid motor as recited in  claim 28  wherein the outer surface of the rotor and the inner surface of the stator are formed from dissimilar materials. 
   
   
       37 . The fluid motor as recited in  claim 36  wherein the outer surface of the rotor and the inner surface of the stator are formed from dissimilar metals. 
   
   
       38 . The fluid motor as recited in  claim 36  wherein one of the outer surface of the rotor and the inner surface of the stator is formed from a nanocomposite material and the other of the outer surface of the rotor and the inner surface of the stator is formed from a metal. 
   
   
       39 . A fluid motor for use in drilling a wellbore that transverses a subterranean formation to impart rotary motion to a drill bit in response to a circulating fluid, the fluid motor comprising:
 a helical stator with (n) lobes, the stator having a stator housing and a stator sleeve, the stator sleeve positioned interiorly of at least a portion of the stator housing, the stator having an inner surface; and   a helical rotor with (n−1) lobes, the rotor having an outer surface that contacts the inner surface of the stator as the rotor rotates and precesses within the stator.   
   
   
       40 . The fluid motor as recited in  claim 39  wherein the stator housing and the stator sleeve are formed from dissimilar materials. 
   
   
       41 . The fluid motor as recited in  claim 40  wherein the stator housing is formed from a metal and the stator sleeve is formed from a nanocomposite material. 
   
   
       42 . The fluid motor as recited in  claim 40  wherein the stator housing and the stator sleeve are formed from dissimilar metals. 
   
   
       43 . The fluid motor as recited in  claim 39  wherein the outer surface of the rotor and the inner surface of the stator are formed from dissimilar materials. 
   
   
       44 . The fluid motor as recited in  claim 43  wherein the outer surface of the rotor and the inner surface of the stator are formed from dissimilar metals. 
   
   
       45 . The fluid motor as recited in  claim 43  wherein one of the outer surface of the rotor and the inner surface of the stator is formed from a nanocomposite material and the other of the outer surface of the rotor and the inner surface of the stator is formed from a metal.