Isolated thrust chamber for esp seal section

Abstract

An electric submersible pumping system for use in pumping fluids from a wellbore includes a motor that is filled with a motor lubricant, a pump driven by the motor, a thrust chamber connected between the motor and the pump, and a seal section. The thrust chamber is filled with thrust chamber lubricant and the motor and seal section are filled with motor lubricant. To prevent the mixing of the thrust chamber lubricant with the motor lubricant, the thrust chamber is in fluid isolation from the motor and the seal section. The electric submersible pumping system may include an upper seal section, a lower seal section or both upper and lower seal sections.

What is claimed is: 
     
         1 . An electric submersible pumping system for use in pumping fluids from a wellbore, the electric submersible pumping system comprising:
 a motor, wherein the motor is filled with a motor lubricant;   a pump driven by the motor;   a thrust chamber connected between the motor and the pump, wherein the thrust chamber is filled with a thrust chamber lubricant; and   a seal section, wherein the seal section is in fluid isolation from the thrust chamber and wherein the seal section is in fluid communication with the motor.   
     
     
         2 . The electric submersible pumping system of  claim 1 , wherein the seal section is an upper seal section that is connected between the thrust chamber and the pump. 
     
     
         3 . The electric submersible pumping system of  claim 2 , wherein the seal section further comprises a seal section shaft that extends from the motor to the upper seal section through the thrust chamber. 
     
     
         4 . The electric submersible pumping system of  claim 3 , wherein the seal section shaft comprises an internal passage that permits the movement of motor lubricant from the motor to the upper seal section. 
     
     
         5 . The electric submersible pumping system of  claim 1 , wherein the seal section is a lower seal section that is connected to the motor. 
     
     
         6 . The electric submersible pumping system of  claim 5 , wherein the lower seal section comprises a sealing mechanism selected from the group consisting of bag seals, bellows, pistons, labyrinths and combinations thereof. 
     
     
         7 . The electric submersible pumping system of  claim 6 , wherein the seal mechanism further comprises one or more discharge ports and wherein each of the one or more discharge ports is configured as a one-way check valve that places the interior of the seal mechanism in fluid communication with the wellbore when opened. 
     
     
         8 . The electric submersible pumping system of  claim 1 , wherein the lower seal section further comprises a fluid exchange assembly and wherein the fluid exchange assembly comprises:
 a solids screen;   exchange ports; and   wherein the fluid exchange assembly is configured to place the exterior of the bladder in fluid communication with the wellbore.   
     
     
         9 . The electric submersible pumping system of  claim 1 , wherein the thrust chamber comprises:
 a piston expansion assembly; and   a thrust bearing assembly.   
     
     
         10 . The electric submersible pumping system of  claim 9 , wherein the piston expansion assembly comprises:
 one or more cylinders;   a piston in each of the one or more cylinders; and   one or more piston stops in each of the one or more cylinders.   
     
     
         11 . The electric submersible pumping system of  claim 1 , wherein the thrust chamber comprises a thrust chamber seal mechanism selected from the group consisting of pistons, bellows, seal bags, labyrinths and combinations thereof. 
     
     
         12 . The electric submersible pumping system of  claim 1 , wherein the motor lubricant is different than the thrust chamber lubricant. 
     
     
         13 . The electric submersible pumping system of  claim 1 , wherein the seal section is an upper seal section connected between the pump and the thrust chamber and wherein the electric submersible pumping system further comprises a lower seal section connected to the motor. 
     
     
         14 . An electric submersible pumping system for use in pumping fluids from a wellbore, the electric submersible pumping system comprising:
 a motor, wherein the motor is filled with a first lubricant;   a pump driven by the motor;   an upper seal section connected to the pump; and   a thrust chamber connected between the motor and the upper seal section, wherein the thrust chamber is filled with a second lubricant that is different than the first lubricant.   
     
     
         15 . The electric submersible pumping system of  claim 14 , wherein the first lubricant is dielectric motor lubricant. 
     
     
         16 . The electric submersible pumping system of  claim 14 , wherein the second lubricant is seal section oil that has a viscosity that is higher than the viscosity of the dielectric motor lubricant. 
     
     
         17 . The electric submersible pumping system of  claim 14 , further comprising a lower seal section connected to the motor, wherein the lower seal section is in fluid communication with the motor. 
     
     
         18 . An electric submersible pumping system for use in pumping fluids from a wellbore, the electric submersible pumping system comprising:
 a motor, wherein the motor is filled with motor lubricant;   a pump driven by the motor;   a lower seal section connected to a lower side of the motor, wherein the lower seal section is in fluid communication with the motor; and   a thrust chamber connected between the motor and the pump, wherein the thrust chamber is filled with thrust chamber lubricant and wherein the thrust chamber is in fluid isolation from the motor.   
     
     
         19 . The electric submersible pumping system of  claim 18 , wherein the thrust chamber comprises:
 a piston expansion assembly; and   a thrust bearing assembly.   
     
     
         20 . The electric submersible pumping system of  claim 19 , wherein the piston expansion assembly comprises:
 one or more cylinders;   a piston in each of the one or more cylinders; and   one or more piston stops in each of the one or more cylinders.