Electric progressive cavity pump

Abstract

An electric progressive cavity pump system includes a progressive cavity pump in operation connection with a six-pole, three-phase electric motor. A method of producing fluid from a wellbore includes the steps of positioning a progressive cavity pump below a fluid level in the wellbore, connecting a six-pole, three-phase electric motor that includes a stator having eighteen slots and a plurality of windings distributed among the eighteen slots, wherein the windings of different phases do not pass through the same slot and operating the progressive cavity pump via the electric motor to produce the fluid from the wellbore. The electric motor may be positioned below the fluid level in the wellbore or at the surface.

What is claimed is: 
     
         1 . A submersible electric progressive cavity pump system, the system comprising:
 a wellbore drilled from the ground surface to a subterranean formation, the wellbore containing a fluid;   a progressive cavity pump positioned in the wellbore below the fluid level; and   a six-pole, three-phase integer slots-per-pole ratio electric motor operatively connected to the progressive cavity pump, wherein the electric motor is positioned above the ground surface, the electric motor comprising:
 a plurality of windings distributed among the slots, each of the plurality of windings comprising two coil sides, one of the two coil sides positioned in a top of one of the plurality of slots and the other of the two coil sides positioned in a bottom of one of the other of the plurality of slots, the plurality of windings are arranged in the plurality of slots such that electrical poles formed by the windings are symmetrically positioned, and wherein the windings of different phases do not pass through the same slot in each of the plurality of slots. 
   
     
     
         2 . The system of  claim 1 , wherein the motor comprises eighteen slots formed symmetrically about a motor stator. 
     
     
         3 . The system of  claim 1 , further comprising a 4:1 ratio gearbox adapted to operate the progressive cavity pump at 300 to 450 revolutions per minute. 
     
     
         4 . The system of  claim 1 , wherein:
 the motor comprises eighteen slots formed symmetrically about a motor stator; and   further comprising a 4:1 ratio gearbox adapted to operate the progressive cavity pump at 300 to 450 revolutions per minute.   
     
     
         5 . The system of  claim 1 , further comprising a gearbox connected between the motor and the progressive cavity pump. 
     
     
         6 . The system of  claim 1 , further comprising a gearbox connected between the motor and the progressive cavity pump, wherein the gearbox is geared to a 4:1 ratio. 
     
     
         7 . The system of  claim 1 , wherein the motor comprises eighteen slots formed symmetrically about a motor stator; and
 further comprising a gearbox connected between the motor and the progressive cavity pump.   
     
     
         8 . The system of  claim 1 , wherein the motor comprises eighteen slots formed symmetrically about a motor stator; and
 further comprising a gearbox geared to a 4:1 ratio connected between the motor and the progressive cavity pump.   
     
     
         9 . The system of  claim 1 , wherein the motor comprises eighteen slots; and
 further comprising a gearbox connected between the motor and the progressive cavity pump.   
     
     
         10 . The system of  claim 1 , wherein the motor comprises eighteen slots; and
 further comprising a gearbox connected between the motor and the progressive cavity pump, the gearbox adapted to operate the progressive cavity pump at about 300 to 450 revolutions per minute.   
     
     
         11 . The system of  claim 1 , wherein the windings of the same phase span 20 degrees. 
     
     
         12 . The system of  claim 11 , wherein the electric motor is positioned above the ground surface. 
     
     
         13 . A method of producing fluid from a wellbore, comprising:
 positioning a progressive cavity pump below a fluid level in the wellbore, the progressive cavity pump connected to a six-pole, three-phase integer slots-per-pole ratio electric motor, the electric motor comprising a plurality of windings distributed among the slots, the plurality of windings are arranged in the plurality of slots such that electrical poles formed by the windings are symmetrically positioned, and wherein the winding of different phases do not pass through the same slot in each of the plurality of slots; and   operating the progressive cavity pump via the electric motor to produce the fluid from the wellbore.   
     
     
         14 . The method of  claim 13 , wherein the electric motor is positioned below the fluid level in the wellbore. 
     
     
         15 . The method of  claim 13 , wherein the electric motor is located above a ground surface from which the wellbore is initiated. 
     
     
         16 . The method of  claim 13 , wherein the electric motor comprises eighteen slots. 
     
     
         17 . The method of  claim 13 , wherein the operating the progressive cavity pump comprises controlling the output of the electric motor via electrical power provided to the electric motor from a variable speed drive positioned above a ground surface. 
     
     
         18 . The method of  claim 13 , wherein the windings of the same phase span 20 degrees.