Linear Drive Assembly with Rotary Union for Well Head Applications and Method Implemented Thereby

Abstract

A drive assembly for a progressive cavity pump includes a frame supported by the wel piping and a polish rod connected to the sucker rod. The polish rod is received by a rotary union formed by a sleeve portion rotatable with respect to a body portion with a seal structure that seals the sleeve and body portions during rotation. A mechanical drive, such as a hydraulic motor, electric motor or engine, has an output shaft that is linear with the polish rod and that has an axial passageway which receives the polish rod. A coupler mechanically couples an upper portion of the polish rod to the output shaft. The invention also includes a method of rotating a progressive cavity pump by this assembly.

1 . A drive assembly for a progressive cavity pump located downhole in a well that is provided with piping and a sucker rod located in an interior region of the piping, comprising:
 (A) a frame including a base portion adapted to be supported by said piping when said drive assembly is in an assembled state;   (B) a polish rod including a lower end portion adapted to be connected to said sucker rod when in the assembled state whereby rotation of said polish rod acts to rotate said sucker rod;   (C) a rotary union including a body portion and a sleeve portion secured together and adapted to receive said polish rod therethrough, said body portion and said sleeve portion being relatively rotatable with respect to one another and including a seal structure operative to substantially seal said body portion and said sleeve portion during rotational movement thereof;   (D) a mechanical drive supported by said frame when in the assembled state and including a drive body and an output shaft extending along a linear drive axis, said output shaft having an axial passageway therethrough that is sized and adapted to receive said polish rod such that said polish rod is surrounded by said drive body, said mechanical drive being selected from a group consisting of hydraulic motors, electric motors, combustion engines, and gear boxes; and   (E) a coupler member operative to mechanically couple said output shaft and an upper portion of said polish rod whereby rotation of said output shaft rotates said polish rod and said sucker rod when in the assembled state.   
   
   
       2 . A drive assembly according to  claim 1  wherein said base portion is adapted to connect to said piping and including a stool portion connected to said base portion and having a stool interior. 
   
   
       3 . A drive assembly according to  claim 2  wherein said rotary union is located in the stool interior when in the assembled state. 
   
   
       4 . A drive assembly according to  claim 1  wherein said sleeve portion matably engages said body portion and including at least one bearing element rotatably supporting said sleeve portion with respect to said body portion. 
   
   
       5 . A drive assembly according to  claim 1  wherein said seal structure includes a first seal element constructed of a carbon material and a second seal element constructed of a ceramic material. 
   
   
       6 . A drive assembly according to  claim 5  wherein said rotary union includes biasing spring operative to bias said first and second seal elements together. 
   
   
       7 . A drive assembly according to  claim 4  wherein said outer body portion has a port formed therein proximate to said seal structure. 
   
   
       8 . A drive assembly according to  claim 1  wherein said outer body portion is threadably connected to said base portion when in the assembled state. 
   
   
       9 . A drive assembly according to  claim 1  including a friction cap connected to an outer sleeve end of said sleeve portion for common rotation therewith when in the assembled state, said friction cap including at least one friction cap seal operative to substantially seal against both said sleeve portion and said polish rod when in the assembled state. 
   
   
       10 . A drive assembly according to  claim 1  wherein said mechanical drive includes a bearing member axially supporting said drive shaft and operative to support a load of at least 5000 pounds. 
   
   
       11 . A drive assembly according to  claim 1  wherein said mechanical drive includes a rotary speed detector operative to monitor rotational speed of said output shaft 
   
   
       12 . A drive assembly according to  claim 11  wherein said rotary speed detector includes a gear element secured to said output shaft and having peripheral gear teeth and further including a proximity switch disposed proximate to the peripheral gear teeth and operative to count consecutive ones of the peripheral teeth when said gear element is rotated thereby to indicate the rotational speed of said output shaft. 
   
   
       13 . A drive assembly according to  claim 1  wherein said output shaft includes an exposed portion extending axially out of said drive body, said exposed portion having a key structure formed thereon, said coupler member having a keyway sized and adapted to engage said key structure. 
   
   
       14 . A drive assembly according to  claim 1  wherein said coupler member is a friction block. 
   
   
       15 . A drive assembly according to  claim 1  including a shield supported by said frame so that said shield is in surrounding relation to said coupler member. 
   
   
       16 . A drive assembly according to  claim 15  including a slinger element interfacing said shield and the upper portion of said polish rod. 
   
   
       17 . A drive assembly according to  claim 1  wherein said mechanical drive is a hydraulic motor and including a hydraulic pump assembly operative to supply pressurized hydraulic fluid to said hydraulic motor. 
   
   
       18 . A drive assembly for a progressive cavity pump located downhole in a well that is provided with piping and a sucker rod located in an interior of the piping, comprising:
 (A) a frame including a base portion adapted to be supported by said piping when said drive assembly is in an assembled state;   (B) a polish rod including a lower end portion adapted to be connected to said sucker rod when in the assembled state whereby rotation of said polish rod acts to rotate said sucker rod;   (C) a rotary union adapted to receive said polish rod therethrough and operative to substantially seal the piping interior while allowing rotation of said polish rod, said rotary union including:
 (1) a body portion; 
 (2) a sleeve portion matably engaging said outer body portion and rotatable with respect thereto; 
 (3) at least one bearing element rotatably supporting said sleeve portion with respect to said body portion; and 
 (4) a first seal element substantially sealing with said sleeve portion; 
 (5) a second seal element substantially sealing with said body portion, said first and second seal elements confronting one another for rotational engagement whereby a substantial seal is maintained between said first and second seal elements during rotation of said sleeve portion relative to said body portion; 
   (D) a mechanical drive supported by said frame when in the assembled state and including an output shaft; and   (E) a coupler member operative to mechanically couple said output shaft and an upper portion of said polish rod whereby rotation of said output shaft rotates said polish rod and said sucker rod when in the assembled state.   
   
   
       19 . A drive assembly according to  claim 18  wherein said first seal element has an annular shape and is constructed of ceramic and wherein said second seal element has and annular shape and is constructed of carbon compound. 
   
   
       20 . A drive assembly according to  claim 18  wherein said second seal element is slideably disposed for axial movement in said body portion. 
   
   
       21 . A drive assembly according to  claim 20  wherein said rotary union includes biasing spring operative to axially bias said first and second seal elements together. 
   
   
       22 . A drive assembly according to  claim 20  including a pair of guide pins mounted to said body portion, said second seal element supported by said guide pins. 
   
   
       23 . A drive assembly according to  claim 18  wherein said body portion of said rotary union has a port formed therein proximate to an interface between said first and second seal elements. 
   
   
       24 . A drive assembly according to  claim 18  wherein said body portion of said rotary union is threadably connected to said base portion when in the assembled state. 
   
   
       25 . A drive assembly according to  claim 18  including a friction cap connected to an outer sleeve end of said sleeve portion of said rotary union for common rotation with said sleeve portion when in the assembled state, said friction cap including at least one friction cap seal operative to substantially seal against both said sleeve portion and said polish rod when in the assembled state. 
   
   
       26 . In a well provided with piping including a casing and a delivery tube extending from a surface location and having a casing interior, said well including a cross-fitting mounted to and upper end of said piping, a progressive cavity pump located downhole in said casing, a sucker rod connected to said progressive cavity pump and extending upwardly toward the surface location and a polish rod connected to said sucker rod whereby rotation of said polish rod acts to rotate said sucker rod and rotation of said sucker rod acts to rotate said progressive cavity pump thereby to pump fluid from a lower portion of said well through said delivery tube for discharge out of said cross-fitting, the improvement comprising a frame including a base portion secured to said cross-fitting and supported by said piping, a rotary union secured to said base portion and operative to substantially seal the piping interior, said rotary union receiving said polish rod therethrough and including a body portion and a sleeve portion secured together and being relatively rotatable with respect to one another and including a seal structure operative to substantially seal said outer body portion and said sleeve during rotational movement thereof, a mechanical drive supported by said frame and including a drive body and an output shaft extending along a linear drive axis, said shaft having an axial passageway therethrough that is sized and adapted to receive said polish rod such that said polish rod is surrounded by said mechanical drive, a coupler member operative to mechanically couple said output shaft and an upper portion of said polish rod whereby rotation of said output shaft rotates said polish rod. 
   
   
       27 . The improvement of  claim 26  wherein said rotary union includes at least one bearing element rotatably supporting said inner sleeve portion with respect to said outer body portion. 
   
   
       28 . The improvement of  claim 26  wherein said seal structure includes a first seal element and a second seal element axially confronting one another. 
   
   
       29 . A drive assembly according to  claim 28  wherein said rotary union includes a biasing spring operative to axially bias said first and second a first seal elements together. 
   
   
       30 . The improvement of  claim 26  wherein said outer body portion has a port formed therein proximate to said first seal element. 
   
   
       31 . The improvement of  claim 26  wherein said outer body portion is threadably connected to said base portion when in the assembled state. 
   
   
       32 . The improvement of  claim 26  including a friction cap connected to an outer sleeve end of said inner sleeve portion for common rotation therewith when in the assembled state, said friction cap including at least one friction cap seal operative to substantially seal against both said sleeve portion and said polish rod when in the assembled state. 
   
   
       33 . The improvement of  claim 26  wherein said mechanical drive is a hydraulic motor that includes a rotary speed detector element operative to monitor rotational speed of said output shaft. 
   
   
       34 . The improvement of  claim 33  wherein said rotary speed detector includes a gear element secured to said output shaft and having peripheral gear teeth and further including a proximity switch disposed proximate to the peripheral gear teeth and operative to count consecutive ones of the peripheral teeth when said gear element is rotated thereby to indicate the rotational speed of said output shaft. 
   
   
       35 . The improvement of  claim 26  wherein said output shaft includes an exposed portion extending axially out of said motor body, said exposed portion having a key structure formed thereon, said coupler member having a keyway sized and adapted to engage said key structure. 
   
   
       36 . A method of rotating a progressive cavity pump located at a downhole location in a well that includes piping extending from a surface location and having an interior and wherein a rotatable sucker rod extends upwardly toward the surface location and wherein a polish rod is connected to said sucker rod whereby rotation of said polish rod acts to rotate said sucker rod and rotation of said sucker rod acts to rotate said progressive cavity pump thereby to pump fluid to the surface location, comprising:
 (A) providing a mechanical drive that includes an axially oriented output shaft with an axial passageway therethrough;   (B) mounting said mechanical drive generally vertically of said piping with said polish rod extending through the axial passageway of said output shaft;   (C) coupling said polish rod and said output shaft whereby rotation of said output shaft will rotate said polish rod;   (D) providing a rotary union between said polish rod and said piping thereby to substantially seal the piping while allowing rotation of said polish rod wherein said rotary union includes a body portion and a sleeve portion that are relatively rotatable with respect to one another and wherein said rotary union includes a seal structure between said body portion and said sleeve portion; and   (E) coupling said sleeve portion to said polish rod in a substantially sealed manner.   
   
   
       37 . A method according to  claim 36  wherein said mechanical drive is supported by a cross-fitting that is supported by said piping. 
   
   
       38 . A method according to  claim 37  including a step of monitoring the rotational speed of said output shaft. 
   
   
       39 . A method according to  claim 38  wherein the step of monitoring the rotational speed is accomplished by detecting the speed of peripheral gear teeth of a gear element mounted to said output shaft. 
   
   
       40 . A method according to  claim 39  wherein detection of the speed of the peripheral gear teeth is accomplished by a proximity switch disposed proximate to the peripheral gear teeth and operative to count consecutive ones of the peripheral teeth when said gear element is rotated thereby to indicate the rotational speed of said output shaft. 
   
   
       41 . A method according to  claim 40  including the step of adjusting the rate of rotation of said output. 
   
   
       42 . A drive assembly according to  claim 41  wherein the mechanical drive is a hydraulic motor and wherein the step of adjusting the rate of rotation of said output shaft is accomplished by varying the selected rate at which hydraulic fluid is pumped through said hydraulic motor. 
   
   
       43 . A drive assembly for a progressive cavity pump located downhole in a well that is provided with piping having an interior and a sucker rod located in the interior, comprising:
 (A) a frame including a base portion adapted to be supported by said piping when said drive assembly is in an assembled state;   (B) a polish rod including a lower end portion adapted to be connected to said sucker rod when in the assembled state whereby rotation of said polish rod acts to rotate said sucker rod;   (C) a rotary union and friction cap assembly adapted to receive said polish rod therethrough and operative to substantially seal the piping interior and to substantially seal against said polish rod while allowing rotation of said polish rod therein when in the assembled state;   (D) a hydraulic motor supported by said frame when in the assembled state and including a motor body and an output shaft extending along a linear drive axis, said shaft having an axial passageway therethrough that is sized and adapted to receive said polish rod such that said polish rod is surrounded by said hydraulic motor; and   (E) a coupler member operative to mechanically couple said output shaft and an upper portion of said polish rod whereby rotation of said output shaft rotates said polish rod and said sucker rod when in the assembled state.