Wellbore esp system with improved magnetic gear

Abstract

An electrical submersible pump system includes at least one electric motor coupled to a mechanism for hanging the pump system in a wellbore. At least one magnetic gear assembly is coupled at its input to an output of the at least one electric motor. A protector assembly is coupled at an input thereof to an output of the at least one magnetic gear assembly. A pump is functionally coupled at its input to a rotational output of the protector assembly. The protector assembly includes a tortuous path assembly having one end of each of a plurality of tortuous paths therein in fluid communication with fluid in the wellbore. The tortuous paths each have another end in fluid communication with dielectric fluid disposed within the protector, the at least one magnetic gear and the at least one electric motor.

What is claimed is: 
     
         1 . An electrical submersible pump system, comprising:
 at least one electric motor coupled to a mechanism for hanging the pump system in a wellbore;   at least one magnetic gear assembly coupled at its input to an output of the motor;   a protector assembly coupled at an input thereof to an output of the at least one magnetic gear assembly; and   a pump functionally coupled at its input to a rotational output of the protector assembly;   wherein the protector assembly comprises a tortuous path assembly having one end of each of a plurality of tortuous paths therein in fluid communication with fluid in the wellbore, the tortuous paths each having another end in fluid communication with dielectric fluid disposed within the protector, the at least one magnetic gear and the at least one electric motor.   
     
     
         2 . The pump system of  claim 1  wherein the pump comprises a progressive cavity pump. 
     
     
         3 . The pump system of  claim 1  further comprising a flexible torque transmission shaft disposed between a rotational output of the protector assembly and a rotational input of the pump. 
     
     
         4 . The pump system of  claim 3  wherein the protector assembly comprises a jointed coupling engaged at one end with the bottom of a drive shaft extending through a housing disposed below the magnetic gear assembly, the jointed coupling engaged at its other end to the flexible torque transmission shaft. 
     
     
         5 . The pump system of  claim 4  wherein the drive shaft is rotatably supported in its housing at both its longitudinal ends by bearings, at least one of the bearings configured to accept thrust loading from the drive shaft to isolate the thrust loading from the at least one magnetic gear assembly. 
     
     
         6 . The pump system of  claim 5  wherein the tortuous path assembly is disposed at a lower end of the drive shaft housing. 
     
     
         7 . The pump system of  claim 1  wherein the hanging mechanism comprises a coupling to join to a lower end of a coiled tubing, and wherein an electrical cable coupled to the pump system is disposed within the coiled tubing. 
     
     
         8 . The pump system of  claim 1  further comprising an electrical connector sub including a connector ring in contact with a first contact pin extending from the at least one electric motor and at least one contact slot in contact with at least a second, longer contact pin extending from the motor. 
     
     
         9 . The pump system of  claim 1  wherein synchronization is mechanically maintained between each of a plurality of magnetic gear assemblies, and of each of a plurality of electric motors. 
     
     
         10 . The pump system of  claim 1  further comprising a variable volume reservoir disposed within the protector assembly and in fluid communication with the dielectric fluid end of the tortuous path assembly. 
     
     
         11 . The pump system of  claim 1  wherein the pump is the furthest downhole rotating part of the pump system.