Reciprocating electrical submersible well pump

Abstract

A downhole pump system includes a magnetically operated rotary to linear motion converter coupled at a rotary input to a drive source. A reciprocating action positive displacement pump having a reciprocating input thereto is coupled to a linear motion output of the magnetically operated rotary to linear motion converter. An intake of the pump is in fluid communication with a wellbore region and a discharge of the pump is in fluid communication with a well conduit extending to Earth's surface.

What is claimed is: 
     
         1 . A downhole pump system, comprising:
 a reciprocating action positive displacement pump having a fluid intake for providing fluid communication with a wellbore region and a fluid discharge for providing fluid communication with a well conduit; and   a magnetically operated rotary to linear motion converter having a rotary motion input to be coupled to a downhole rotary drive source, and a linear reciprocating motion output coupled to a linear reciprocating motion input of the reciprocating action positive displacement pump.   
     
     
         2 . The downhole pump system of  claim 1 , wherein the magnetically operated rotary to linear motion converter comprises:
 a pair of axially arranged outer magnet assemblies each having at least one pair of circumferentially arranged opposed magnetic poles; and   an inner magnet assembly positioned axially intermediate the outer magnet assemblies, wherein the inner magnet assembly comprises at least one pair of circumferentially arranged opposed magnetic poles.   
     
     
         3 . The downhole pump system of  claim 2 , wherein at least a portion of a magnetic field developed by each of the pair of outer magnet assemblies and the inner magnet assembly extends in an axial direction such that relative rotation between the pair of outer magnet assemblies and the inner magnet assembly causes a cyclical alignment and misalignment between the magnetic poles of the inner and outer magnet assemblies, causing one of the inner and outer magnet assemblies to linearly reciprocate. 
     
     
         4 . The downhole pump system of  claim 2 , wherein the opposed poles of one outer magnet assembly are circumferentially aligned in-phase with the opposed poles of the other outer magnet assembly. 
     
     
         5 . The downhole pump system of  claim 2 , wherein the opposed poles of one outer magnet assembly are circumferentially misaligned out-of-phase with the opposed poles of the other outer magnet assembly. 
     
     
         6 . The downhole pump system of  claim 2 , wherein the pair of outer magnet assemblies and the inner magnet assembly each comprises a single pair of opposed magnetic poles. 
     
     
         7 . The downhole pump system according to  claim 2 , wherein at least one of the pair of outer magnet assemblies comprises multiple pairs of circumferentially arranged opposed magnetic poles, and the inner magnet assembly comprises an equal number of pairs of circumferentially arranged opposed magnetic poles. 
     
     
         8 . The downhole pump system according to  claim 2 , wherein at least one of the pair of outer magnet assemblies includes a radially polarized magnetic ring having two or more radially polarized, opposed polarity magnet segments. 
     
     
         9 . The downhole pump system according to  claim 2 , wherein the inner magnet assembly comprises a plurality of longitudinally polarized magnet segments coupled to each other in opposed polarity. 
     
     
         10 . The downhole pump system according to  claim 2 , further comprising a plurality of pairs of axially spaced outer magnet assemblies, and at least one inner magnet assembly positioned between each of the plurality of pairs of outer magnet assemblies. 
     
     
         11 . The downhole pump system according to  claim 2 , wherein the rotary input of the magnetically operated rotary to linear motion converter is coupled to the pair of outer magnet assemblies, and the linear reciprocating motion output of the magnetically operated rotary to linear motion converter is coupled to the inner magnet assembly. 
     
     
         12 . The downhole pump system according to  claim 2 , wherein the rotary input of the magnetically operated rotary to linear motion converter is coupled to the inner magnet assembly, and the linear reciprocating motion output of the magnetically operated rotary to linear motion converter is coupled to the pair of outer magnet assemblies. 
     
     
         13 . The downhole pump system according to  claim 1 , further comprising a magnetic control arrangement for directing a magnetic field associated with the magnetically operated rotary to linear motion converter. 
     
     
         14 . The downhole pump system according to  claim 1 , further comprising a downhole rotary drive source. 
     
     
         15 . The downhole pump system according to  claim 14 , wherein the downhole rotary drive source comprises an electric motor. 
     
     
         16 . The downhole pump system according to  claim 14 , wherein at least a portion of the downhole rotary drive source and the rotary input to the magnetically operated rotary to linear motion converter are disposed in a sealed housing at least partially filled with a dielectric fluid. 
     
     
         17 . The downhole pump system according to  claim 16 , wherein an interior of the sealed housing is pressure compensated to equalize pressure therein to an external fluid pressure. 
     
     
         18 . The downhole pump system according to  claim 16 , wherein the sealed housing is made from a non-magnetic metal. 
     
     
         19 . The downhole pump system according to  claim 1 , wherein the reciprocating action positive displacement pump comprises a valve body having a passively actuated intake valve and a passively actuated discharge valve. 
     
     
         20 . The downhole pump system according to  claim 19 , wherein at least one of the intake valve and the discharge valve comprises at least one of a disk valve, a poppet valve and a ball valve. 
     
     
         21 . The downhole pump system according to  claim 20 , wherein the intake valve comprises a valve member having a stem disposed in a bore in a pushrod, wherein the pushrod is coupled to the linear motion output of the magnetically operated rotary to linear motion converter, the bore and the stem configured to cause immediate opening of the intake valve and damped closing thereof. 
     
     
         22 . A method for pumping a fluid from a wellbore region, the method comprising:
 operating a reciprocating action positive displacement pump within a wellbore and establishing fluid communication between a fluid intake of the pump and the wellbore region, and establishing fluid communication between a fluid discharge of the reciprocating action positive displacement pump and a well conduit, wherein a linear reciprocating motion input of the pump is coupled to a linear reciprocating motion output of a magnetically operated rotary to linear motion converter; and     
     
     
         23 .  operating a rotary drive from a downhole rotary drive source coupled to a rotary motion input of the magnetically operated rotary to linear motion converter to operate the reciprocating action positive displacement pump. The method according to  claim 23  further comprising directing a discharge of the reciprocating action positive displacement pump through a well conduit to a surface end of wellbore.