Seal assembly for a submersible pumping system and an associated method thereof

Abstract

A seal assembly for a submersible pumping system is presented. The seal assembly includes a support tube configured to surround a shaft. Further, the seal assembly includes a first bag positioned surrounding the support tube to define a first chamber between the first bag and the support tube, wherein the first chamber is configured to contain a motor fluid. Also, the seal assembly includes a second bag positioned surrounding the first bag to define a second chamber between the first bag and the second bag. In addition, the seal assembly includes an impermeable device disposed in the second chamber and configured to isolate the motor fluid from a wellbore fluid.

1 . A seal assembly for a submersible pumping system, the seal assembly comprising:
 a support tube configured to surround a shaft;   a first bag positioned surrounding the support tube to define a first chamber between the first bag and the support tube, wherein the first chamber is configured to contain a motor fluid;   a second bag positioned surrounding the first bag to define a second chamber between the first bag and the second bag; and   an impermeable device disposed in the second chamber and configured to isolate the motor fluid from a wellbore fluid.   
     
     
         2 . The seal assembly of  claim 1 , further comprising:
 a first plate coupled to a first end of the support tube and a first end of the first and second bags; and   a second plate coupled to a second end of the support tube and a second end of the first and second bags.   
     
     
         3 . The seal assembly of  claim 1 , wherein the impermeable device, the first bag, and the second bag are configured to expand in response to expansion of the motor fluid in the first chamber. 
     
     
         4 . The seal assembly of  claim 1 , wherein the impermeable device, the first bag, and the second bag are configured to contract in response to contraction of the motor fluid in the first chamber. 
     
     
         5 . The seal assembly of  claim 1 , wherein the impermeable device comprises a metal foil positioned between the first bag and the second bag. 
     
     
         6 . The seal assembly of  claim 5 , wherein the metal foil comprises two or more segments positioned adjacent to each other, wherein each of the segments is partially overlapped to an adjacent segment to form a shiplap arrangement. 
     
     
         7 . The seal assembly of  claim 5 , wherein the metal foil comprises a plurality of folded segments configured to unfold in response to expansion of the motor fluid. 
     
     
         8 . The seal assembly of  claim 1 , wherein the impermeable device comprises a buffer fluid. 
     
     
         9 . The seal assembly of  claim 8 , wherein the buffer fluid is configured to absorb or repel water molecules of the wellbore fluid when the water molecules permeate through the second bag. 
     
     
         10 . The seal assembly of  claim 8 , wherein the buffer fluid comprises at least one property which is modified based on deleterious ingredients of the wellbore fluid. 
     
     
         11 . The seal assembly of  claim 1 , wherein at least one of the first bag and the second bag comprises a plurality of metallic fibers. 
     
     
         12 . The seal assembly of  claim 11 , wherein the plurality of metallic fibers is weaved to form a fabric or cloth layer having a predetermined flexibility. 
     
     
         13 . The seal assembly of  claim 11 , wherein the impermeable device comprises a metal foil attached to the metallic fibers. 
     
     
         14 . The seal assembly of  claim 1 , further comprising:
 a third bag positioned surrounding the second bag to define a third chamber between the second bag and the third bag; and   an additional impermeable device disposed in the third annular chamber and configured to restrict a flow of the wellbore fluid into the motor fluid.   
     
     
         15 . The seal assembly of  claim 1 , wherein the impermeable device is coupled to at least one of the first bag and the second bag. 
     
     
         16 . A submersible pumping system comprising:
 an electric motor;   a pump coupled to the electric motor and configured to pump a wellbore fluid; and   a seal assembly positioned between the pump and the electric motor, wherein the seal assembly comprises:
 a support tube configured to surround a shaft; 
 a first bag positioned surrounding the support tube to define a first chamber between the first bag and the support tube, wherein the first chamber is configured to contain a motor fluid; 
 a second bag positioned surrounding the first bag to define a second chamber between the first bag and the second bag; and 
 an impermeable device disposed in the second chamber and configured to isolate the motor fluid from a wellbore. 
   
     
     
         17 . The submersible pumping system of  claim 16 , further comprising:
 a first plate coupled to a first end of the support tube and a first end of the first and second bags; and   a second plate coupled to a second end of the support tube and a second end of the first and second bags.   
     
     
         18 . The submersible pumping system of  claim 16 , wherein the impermeable device comprises at least a metal foil configured to expand in response to expansion of the motor fluid in the first chamber. 
     
     
         19 . The submersible pumping system of  claim 16 , wherein the impermeable device comprises a buffer fluid configured to absorb or repel water molecules of the wellbore fluid when the water molecules permeate through the second bag. 
     
     
         20 . A method comprising:
 disposing a first bag around a support tube to define a first chamber between the first bag and the support tube, wherein the support tube is configured to support a shaft and the first chamber is configured to store a motor fluid;   disposing a second bag around the first bag to define a second chamber between the first bag and the second bag; and   positioning an impermeable device in the second chamber, wherein the impermeable device is configured to isolate the motor fluid from a wellbore fluid.   
     
     
         21 . The method of  claim 20 , further comprising:
 coupling a first plate to a first end of the first and second bags to a first end of the support tube; and   coupling a second plate to a second end of the first and second bags to a first end of the support tube.