Pump shaft bearing support

Abstract

A device and method of tailoring a pump lift capacity of a pump for an electrical submersible pumping unit (ESP). The pump unit of the ESP has a plurality of stages, each made up of an impeller and a diffuser. The ESP has a pump lift capacity, which is ideally matched with well capacity. The well capacity is, therefore, the target lift capacity. To facilitate matching of pump lift capacity and well capacity, one or more stages of the pump unit may be replaced with a spacer assembly to reduce pump lift capacity by a desired amount. The spacer assembly may include a shaft bearing support made up of an outer ring and an inner ring, wherein the outer and inner ring are connected by webs, which allow oil to flow through the support. The spacer assembly may be axially located on the pump shaft via compression tubes.

1 . A pump unit for an centrifugal pump comprising:
 a pump unit having an intake end and an output end, said pump unit including a housing;   a pump shaft extending through said housing;   a plurality of impellers affixed to said pump shaft for rotating with said pump shaft;   a diffuser adjacent to each of said impellers for directing fluid flow towards a center of said housing;   wherein each pair of said impellers and said diffusers comprises a stage;   a spacer assembly surrounding a portion of said pump shaft within said housing;   a motor in communication with said pump shaft, said motor for rotating said pump shaft.   
     
     
         2 . The pump unit according to  claim 1  wherein said spacer assembly comprises:
 a shaft bearing support; 
 wherein the shaft bearing support minimizes deflection of said pump shaft while the pump unit is in operation. 
 
     
     
         3 . The pump unit according to  claim 2  wherein said shaft bearing support comprises:
 an outer ring that defines an outside diameter of said shaft bearing support; 
 an inner ring that defines an inside diameter of said shaft bearing support; 
 a plurality of webs for connecting said outer ring to said inner ring, said webs defining a plurality of voids therebetween; 
 wherein said inner ring is sized to receive said pump shaft. 
 
     
     
         4 . The pump unit according to  claim 2  wherein said spacer assembly further comprises a first compression tube adjacent to a first side of said shaft bearing support. 
     
     
         5 . The pump unit according to  claim 2  wherein said spacer assembly further comprises:
 a second compression tube adjacent to a second side of said shaft bearing support. 
 
     
     
         6 . The pump unit according to  claim 3  wherein said webs of said shaft bearing support are tapered. 
     
     
         7 . The pump unit according to  claim 3  wherein said webs of said shaft bearing support are angled. 
     
     
         8 . The pump unit according to  claim 3  wherein said webs of said shaft bearing support are twisted. 
     
     
         9 . The pump unit according to  claim 3  further comprising:
 a first compression tube adjacent to a first side of said shaft bearing support; and 
 wherein said first compression tube has a diameter approximately equal to said outer ring of said shaft bearing support. 
 
     
     
         10 . A well comprising:
 a wellhead;   casing extending below said wellhead;   tubing extending downwardly from said wellhead within said casing;   a pump unit having an intake end and an output end, said output end affixed to said tubing for delivering fluids to said tubing, said pump unit including a housing;   a pump shaft extending through said housing;   a plurality of impellers affixed to said pump shaft for rotating with said housing;   a diffuser adjacent to each of said impellers for directing fluid flow towards a center of said housing;   wherein each pair of said impellers and said diffusers comprises a stage;   a spacer assembly surrounding a portion of said pump shaft within said housing;   a motor in communication with said pump shaft, said motor for rotating said pump shaft.   
     
     
         11 . The well according to  claim 10  wherein said spacer assembly comprises:
 a shaft bearing support; 
 wherein the shaft bearing support minimizes deflection of said pump shaft while said pump unit is in operation. 
 
     
     
         12 . The well according to  claim 11  wherein said shaft bearing support comprises:
 an outer ring that defines an outside diameter of said shaft bearing support; 
 an inner ring that defines an inside diameter of said shaft bearing support, 
 a plurality of webs for connecting said outer ring to said inner ring, said webs defining a plurality of voids therebetween; 
 wherein said inner ring is sized to receive said pump shaft. 
 
     
     
         13 . The well according to  claim 11  wherein said spacer assembly comprises:
 a first compression tube adjacent to a first side of said shaft bearing support. 
 
     
     
         14 . The well according to  claim 13  wherein said spacer assembly comprises:
 a second compression tube adjacent to a second side of said shaft bearing support. 
 
     
     
         15 . The well according to  claim 12  wherein said webs of said shaft bearing support are tapered. 
     
     
         16 . The well according to  claim 12  wherein said webs of said shaft bearing support are angled. 
     
     
         17 . The well according to  claim 12  wherein said webs of said shaft bearing support are twisted. 
     
     
         18 . The well according to  claim 12  further comprising:
 a first compression tube adjacent a first side of said shaft bearing support; and 
 wherein said first compression tube has a diameter approximately equal to said outer ring of said shaft bearing support. 
 
     
     
         19 . A method of tailoring a pump lift capacity of a pump for an electrical submersible pumping unit comprising the steps of:
 determining a target pump lift capacity;   selecting a pump having a stage and series sized to have a pump lift capacity greater than said target pump lift capacity;   removing at least one stage from said pump;   replacing said at least one stage with a spacer assembly for reducing said pump lift capacity to more closely match said target pump lift capacity.