Rotary Motor Driven Reciprocating Downhole Pump Assembly

Abstract

A motor and pump assembly for use in a wellbore includes a downhole motor producing a rotary output, a reciprocating plunger for pumping fluid up a tubing string, and a drive linkage supported within the hollow tubular housing having a rotary input in connection with the rotary output of the motor and a reciprocating output which is arranged for longitudinal sliding movement with the reciprocating plunger and which is driven responsive to rotation of the rotary input to drive the plunger. The drive linkage includes a lead screw, a sleeve member having a closed end coupled to the plunger, and a follower supported on an inner side of the sleeve member in operative connection to the lead screw to drive longitudinal sliding movement of the sleeve member responsive to rotation of the lead screw.

1 . A motor and pump assembly for use in a wellbore with a production tubing string having a production passage therein and at least one pump control line alongside the production tubing string, the pump assembly comprising:
 a motor housing portion comprising:
 a hollow tubular housing arranged to be supported at a bottom end of the production tubing string; 
 a motor supported within the hollow tubular housing for connection to said at least one pump control line for driving rotation of a rotary output of the motor; 
 a drive linkage supported within the hollow tubular housing having a rotary input in connection with the rotary output of the motor and a reciprocating output which is arranged for longitudinal sliding movement relative to the hollow tubular housing responsive to rotation of the rotary input; and 
 an auxiliary conduit extending externally alongside the hollow tubular housing and having a production passage therein for connection in series with the production passage of the production tubing string; 
   a plunger housing portion comprising:
 a hollow tubular housing arranged to be supported at the bottom end of the production tubing string in series with the hollow tubular housing portion of the motor housing portion, the hollow tubular housing portion of the plunger housing portion having a production passage therein for connection in series with the production passages of the auxiliary conduit and the production tubing string; 
 a stationary check valve supported at a stationary location within the hollow tubular housing of the plunger housing portion to span across the production passage therein so as to be operable to only allow an upward flow of production fluid therethrough; 
 a plunger supported within the production passage of the plunger housing portion so as to be longitudinally slidable relative to stationary check valve; 
 a movable check valve supported on the plunger for longitudinal sliding movement together with the plunger relative to the plunger housing portion, the movable check valve being operable to only allow an upward flow of production fluid therethrough. 
   
     
     
         2 . The assembly according to  claim 1  wherein the drive linkage comprises:
 a lead screw which is rotatable with the rotary input at a stationary position in the longitudinal direction relative to the motor housing portion; 
 a sleeve member supported within the hollow tubular housing of the motor housing portion for longitudinal sliding movement, the sleeve member having a hollow interior extending longitudinally between an open end receiving the lead screw therein and a closed end coupled to the plunger; and 
 a follower supported on an inner side of the sleeve member in operative connection to the lead screw to drive longitudinal sliding movement of the sleeve member responsive to rotation of the lead screw. 
 
     
     
         3 . The assembly according to  claim 2  wherein the follower comprising a plurality of planetary screws rotatably supported on the sleeve member at circumferentially spaced apart locations about the lead screw. 
     
     
         4 . The assembly according to  claim 2  further comprising an annular sealing member in operative connection between the sleeve member and the housing tubular housing of the motor housing portion so as to isolate the lead screw from the production passage of the plunger housing portion. 
     
     
         5 . The assembly according to  claim 4  further comprising hydraulic oil contained in a closed chamber surrounding the lead screw. 
     
     
         6 . The assembly according to  claim 1  further comprising an end sub supported at a bottom end of the production tubing string and having a plurality of inlet openings at a bottom end of the end sub such that the production passages of the plunger housing portion and the auxiliary conduit are connected in series between the production passage of the production tubing string thereabove and the inlet openings of the end sub therebelow. 
     
     
         7 . The assembly according to  claim 1  wherein the motor housing portion is supported below the plunger housing portion. 
     
     
         8 . The assembly according to  claim 7  wherein said at least one pump control line extends externally alongside the plunger housing portion. 
     
     
         9 . The assembly according to  claim 1  wherein the motor housing portion is supported above the plunger housing portion and wherein the production passage of the auxiliary conduit communicates in series between the production passage of the plunger housing portion therebelow and the production passage of the tubing string thereabove. 
     
     
         10 . The assembly according to  claim 1  wherein the motor comprises a hydraulic motor and said at least one pump control line comprises a first hydraulic line and a second hydraulic line connected in a loop between the motor and a hydraulic supply at a wellhead of the wellbore for driving the motor. 
     
     
         11 . The assembly according to  claim 10  further comprising a hydraulic switching motor arranged to periodically reverse flow in the first and second hydraulic lines so as to periodically reverse rotation of the rotary input and corresponding longitudinal movement of the reciprocating output of the drive linkage. 
     
     
         12 . The assembly according to  claim 1  wherein the motor comprises an electric submersible motor and said at least one pump control line comprises an electric circuit in communication between the electric submersible motor and a power source at a wellhead of the wellbore for driving the motor. 
     
     
         13 . A drive assembly for use in a wellbore with a production tubing string supporting a reciprocating pump assembly at a bottom end thereof, and including at least one pump control line alongside the production tubing string, the drive assembly comprising:
 a hollow tubular housing arranged to be supported at a bottom end of the production tubing string in series with the reciprocating pump assembly;   a motor supported within the hollow tubular housing for connection to said at least one pump control line for driving rotation of a rotary output of the motor; and   a drive linkage supported within the hollow tubular housing having a rotary input in connection with the rotary output of the motor and a reciprocating output which is arranged for connection to the reciprocating pump assembly;   the drive linkage comprising:
 a lead screw which is rotatable with the rotary input at a stationary position in the longitudinal direction relative to the motor housing portion; 
 a sleeve member supported within the hollow tubular housing for longitudinal sliding movement, the sleeve member having a hollow interior extending longitudinally between an open end receiving the lead screw therein and a closed end including a coupling for connection to the reciprocating motor; and 
 a follower supported on an inner side of the sleeve member in operative connection to the lead screw to drive longitudinal sliding movement of the sleeve member responsive to rotation of the lead screw. 
   
     
     
         14 . The drive assembly according to  claim 13  wherein the follower comprising a plurality of planetary screws rotatably supported on the sleeve member at circumferentially spaced apart locations about the lead screw. 
     
     
         15 . The drive assembly according to  claim 13  further comprising an annular sealing member in operative connection between the sleeve member and the housing tubular housing so as to isolate the lead screw from production fluids within a production passage of the reciprocating pump assembly. 
     
     
         16 . The drive assembly according to  claim 15  further comprising hydraulic oil contained in a closed chamber surrounding the lead screw.