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

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.

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.

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.

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.