Progressive cavity pump

Abstract

An electric submersible progressing cavity pump (ESPCP) assembly that restricts reverse rotation of the pump motor and provides for efficient motor shutdown in the event of reverse rotation is disclosed. When the ESPCP rotates in a reverse direction, components associated with the rotating motor shaft stop rotation of the shaft to increase the torque and current of the motor, and the increased torque/current on the motor actuates a torque or current limit switch to shut off the motor. Also, particle and gas separation mechanisms are disclosed, which separate particulates and gas from the fluid flowing into the pump so that the fluid that reaches the rotor and stator assembly has a higher proportion of liquid than the resident well fluid.

1 . An electric submersible progressing cavity pump assembly comprising:
 a motor having a shaft defining a longitudinal axis, said shaft rotatable in a forward direction and in a reverse direction;   a coupling rotatably fixed to said shaft;   a collar releasably coupled with said coupling, said collar movable along said longitudinal axis;   a bracket attached to said motor and at least partially surrounding said collar, said bracket comprising at least one stationary stop;
 said collar positionable in a first position adjacent said coupling when said shaft is rotated in said forward direction; and 
 said collar displaceable from said coupling along said longitudinal axis to a second position in which said collar contacts said at least one stationary stop when said shaft is rotated in said reverse direction. 
   
     
     
         2 . The pump assembly of  claim 1 , further comprising a torque detection switch, said torque detection switch operable to stop said motor when said collar contacts said at least one stationary stop. 
     
     
         3 . The pump assembly of  claim 1 , further comprising a current detection switch, said current detection switch operable to stop said motor when said collar contacts said at least one stationary stop. 
     
     
         4 . The pump assembly of  claim 1 , wherein said coupling and said collar comprise respective surfaces disposed substantially parallel to said longitudinal axis, said surfaces in driving contact with one another with said shaft is rotated in said forward direction and said surfaces spaced from one another when said shaft is rotated in said reverse direction. 
     
     
         5 . The pump assembly of  claim 1 , wherein said collar further comprises at least one ramped surface, said at least one ramped surface contacting said at least one stationary stop when said shaft is rotated in said reverse direction. 
     
     
         6 . The pump assembly of  claim 1 , wherein said collar further comprises an outer circumference and at least one vane situated along said outer circumference, said at least one vane contacting said at least one stationary stop when said shaft is rotated in said reverse direction. 
     
     
         7 . The pump assembly of  claim 6 , wherein said at least one vane is angled such that a first force, urging said collar into said first position, is applied to each said vane when said collar is rotated in said forward direction, and a second force, urging said collar into said second position, is applied to each said vane when said collar is rotated in said reverse direction. 
     
     
         8 . The pump assembly of  claim 6 , comprising a plurality of said vanes, said plurality of vanes defining a plurality of circumferential gaps each disposed between a respective pair of said vanes. 
     
     
         9 . The pump assembly of  claim 1 , wherein said coupling comprises a first ramp surface and said collar comprises an second ramp surface complementary to said first ramp surface, said first and second ramp surfaces sliding with respect to one another to urge said collar into said second position when said shaft is rotated in said reverse direction. 
     
     
         10 . The pump assembly of  claim 1 , wherein said bracket further comprises at least one fluid inlet. 
     
     
         11 . An electric submersible progressing cavity pump assembly for pumping a fluid having entrained particulates, comprising:
 a motor having a rotatable shaft defining a longitudinal axis;   a pump mechanism driven by said shaft to pump the fluid;   a shell disposed intermediate said motor and said pump assembly, said shell including at least one slot; and   an inducer at least partially disposed within said shell, said inducer driven by said shaft for rotation about said longitudinal axis, said inducer operable to centrifugally urge particulates in the fluid outwardly from said shell through said at least one slot.   
     
     
         12 . The pump assembly of  claim 11 , wherein said inducer comprises a helical thread. 
     
     
         13 . The pump assembly of  claim 11 , wherein said inducer is formed of a resilient material and overlies said shaft. 
     
     
         14 . The pump assembly of  claim 11 , wherein said shell comprises a plurality of said slots, said slots disposed in a helically staggered, spaced relation with respect to one another along a length of said shell. 
     
     
         15 . An electric submersible progressing cavity pump assembly for pumping a fluid having entrained gas bubbles, comprising:
 a motor having a rotatable shaft defining a longitudinal axis;   a pump mechanism driven by said shaft to pump the fluid;   a shell disposed intermediate said motor and said pump assembly and comprising at least one hole; and   a gas separator at least partially disposed within said shell, said gas separator operable to channel entrained gas bubbles in the fluid outwardly from said shell through said at least one hole.   
     
     
         16 . The pump assembly of  claim 15 , wherein said gas separator is a crossover device comprising at least one port, each said port of said crossover aligned with a respective said hole in said shell. 
     
     
         17 . The pump assembly of  claim 16 , wherein said crossover device further comprises a wall disposed with said shell, said wall including at least one port, said port spaced from said shaft and disposed radially adjacent said shell. 
     
     
         18 . The pump assembly of  claim 17 , wherein said crossover device comprises a plurality of said walls having a respective plurality of said ports, and a plurality of circumferentially spaced channels defined between respective pairs of said walls, said channels aligned with respective said ports. 
     
     
         19 . The pump assembly of  claim 16 , wherein said crossover device further comprises a top opening, and a penetrable resilient gas barrier positioned in said top opening. 
     
     
         20 . The pump assembly of  claim 16 , wherein said crossover device further comprises a top opening, said shaft extending through said top opening. 
     
     
         21 . The pump assembly of  claim 15 , wherein said gas separator further comprises a gas slinger rotatable with said shaft.