Upthrust Module for Well Fluid Pump

Abstract

A well fluid pump assembly includes a rotary pump having a rotatable pump shaft. A motor is cooperatively engaged with the pump shaft for rotating the pump shaft. An upthrust module has an upthrust module housing having a lower end secured by a threaded engagement to an upper end of the pump. An upthrust module shaft is rotatably mounted in the housing and has a lower end in engagement with an upper end of the pump shaft for transferring upthrust on the pump shaft to the upthrust module shaft. An upthrust base is stationarily mounted in the housing. An upthrust runner is mounted to the upthrust module shaft for rotation therewith and located below the upthrust base. The upthrust runner engages the upthrust base to transfer to the housing upthrust applied to the upthrust module shaft from the pump shaft.

1 . A well fluid pump assembly, comprising:
 a rotary pump having a rotatable pump shaft;   a motor cooperatively engaged with the pump shaft for rotating the pump shaft;   an upthrust module, comprising:   an upthrust module housing having a lower end secured by a threaded engagement to an upper end of the pump;   an upthrust module shaft rotatably mounted in the housing and having a lower end in engagement with an upper end of the pump shaft for transferring upthrust on the pump shaft to the upthrust module shaft;   an upthrust base stationarily mounted in the housing; and   an upthrust runner mounted to the upthrust module shaft for rotation therewith and located below the upthrust base, the upthrust runner engaging the upthrust base to transfer to the housing upthrust applied to the upthrust module shall from the pump shaft.   
     
     
         2 . The assembly according to  claim 1 , further comprising:
 a well fluid discharge adapter on an upper end of the upthrust module for connection to a string of production tubing.   
     
     
         3 . The assembly according to  claim 1 , further comprising:
 a well fluid flow passage extending through the upthrust module for flowing well from the pump through the upthrust module and to a wellhead.   
     
     
         4 . The assembly according to  claim 1 , further comprising:
 a well fluid flow passage extending through the housing for flowing well fluid from the pump through the upthrust module; and wherein   the upthrust runner and the upthrust base are positioned in the housing for immersion in the well fluid flowing through the upthrust module.   
     
     
         5 . The assembly according to  claim 1 , further comprising:
 upper and lower radial support hearings mounted around the upthrust module shaft in the housing;   the upper radial support bearing being located above the thrust runner and the upthrust base; and   the lower radial support bearing located below the thrust runner and the upthrust base.   
     
     
         6 . The assembly according to  claim 1 , wherein the upthrust module shaft is free to move axially a limited extent relative to the housing. 
     
     
         7 . The assembly according to  claim 1 , wherein:
 the upper end of the pump shaft and the lower end of the upthrust module shaft are splined; and   a coupling sleeve with internal splines couples the upper end of the pump shaft and the lower end of the upthrust module shaft to each other for rotation therewith.   
     
     
         8 . The assembly according to  claim 1 , further comprising:
 a radial support bearing mounted in the housing through which the upthrust module shaft extends; and wherein   the upthrust base is mounted to a lower side of the radial support bearing.   
     
     
         9 . The assembly according to  claim 1 , further comprising:
 a below pump thrust bearing located below the pump and in cooperative engagement with the pump shaft for accommodating downthrust imposed on the pump shaft.   
     
     
         10 . The assembly according to  claim 1 , further comprising:
 a seal section mounted above the motor and below the pump, the seal section having a seal section housing containing a movable element to reduce a pressure differential between well fluid exterior of the motor and motor lubricant in the motor;   a seal section shaft rotatably mounted in the seal section housing, the seal section shaft having an upper end in engagement with a lower end of the pump shaft; and   a below-pump thrust bearing located in the seal section housing in engagement with the seal section shaft for accommodating downthrust imposed on the pump shaft, the below-pump thrust bearing being immersed in motor lubricant contained in the seal section housing.   
     
     
         11 . A submersible well pump assembly, comprising:
 a rotary pump having a rotatable pump shaft, the pump having a discharge on an upper end for pumping well fluid up a well;   a motor located below the pump and cooperatively engaged with the pump shaft for rotating the pump shaft;   a lower thrust bearing mounted below the pump and in cooperative engagement with the pump shaft for absorbing downthrust applied to the pump shaft, the lower thrust bearing being immersed in a lubricant that is sealed from well fluid in the well; and   an upper thrust bearing mounted to the discharge of the pump such that the upper thrust bearing is immersed in well fluid pumped by the pump out the discharge, the upper thrust bearing being in cooperative engagement with the pump shaft for absorbing upthrust on the pump shaft.   
     
     
         12 . The assembly according to  claim 11 , wherein the upper thrust bearing comprises:
 an upthrust module housing having a lower end secured by a threaded engagement to the discharge of the pump;   an upthrust module shaft rotatably mounted in the housing and having a lower end in engagement with an upper end of the pump shaft for transferring upthrust on the pump shaft to the upthrust module shaft;   an upthrust base stationarily mounted in the housing; and   an upthrust runner mounted to the upthrust module shaft for rotation therewith and located below the upthrust base, the upthrust runner being axially movable with the upthrust module shaft and rotatably engaging the upthrust base to transfer to the housing upthrust applied to the upthrust module shaft from the pump shaft.   
     
     
         13 . The assembly according to  claim 12 , further comprising:
 a well fluid discharge adapter on an upper end of the upthrust module for connection to a string of production tubing.   
     
     
         14 . The assembly according to  claim 12 , further comprising:
 upper and lower radial support hearings mounted around the upthrust module shaft in the housing;   the upper radial support bearing being located above the thrust runner and the upthrust base, and the lower radial support bearing located below the thrust runner and the upthrust base; and   each of the upper and lower radial support bearings having a well fluid flow passage for flowing well fluid from the discharge of the pump through the housing.   
     
     
         15 . The assembly according to  claim 12 , further comprising:
 upper and lower radial support bearings mounted around the upthrust module shaft in the housing;   the upthrust base being mounted to a lower side of the upper radial support bearing;   the upper and lower radial support bearings each having a well fluid flow passage; and wherein   annular clearances surround the upthrust base and upthrust runner within the housing flowing well fluid from the discharge of the pump through the housing.   
     
     
         16 . The assembly according to  claim 12 , wherein the upthrust module shaft is free to move axially a limited extent relative to the housing. 
     
     
         17 . A method of pumping well fluid, comprising:
 (a) cooperatively coupling a motor to a rotary pump having a rotatable pump shaft and a discharge end;   (b) providing an upthrust module with an upthrust module housing, an upthrust module shaft rotatably mounted in the housing, an upthrust base stationarily mounted in the housing, and an upthrust runner mounted to the upthrust module shaft for rotation therewith;   (c) securing the upthrust module housing to the discharge end of the pump and coupling the upthrust module shaft to the pump shaft;   (d) operating the pump to pump well fluid out the discharge end and through the upthrust module housing; and   (e) during upthrust of sufficient magnitude, pushing the upthrust module shaft upward with the pump shaft, causing the upthrust runner to engage the upthrust base and transfer upthrust imposed on the upthrust module shaft to the upthrust runner.   
     
     
         18 . The method according to  claim 17 , wherein:
 step (d) comprises immersing the upthrust base and the upthrust runner in the well fluid flowing through the upthrust module housing.   
     
     
         19 . The method according to  claim 17 , further comprising:
 in step (a), mounting a downthrust bearing between the motor and the pump; and   during downthrust, transferring downthrust imposed on the pump shaft to the downthrust bearing.   
     
     
         20 . The method according to  claim 17 , wherein:
 step (d) comprises lowering the motor and the pump into well fluid within a well;   step (d) further comprises immersing the upthrust base and the upthrust runner in the well fluid flowing through the upthrust module housing; and wherein the method further comprises:   in step (a), mounting a downthrust bearing within a lubricated environment between the motor and the pump that is sealed from the well fluid; and   during downthrust, transferring downthrust imposed on the pump shaft to the downthrust bearing.