Labyrinth Chamber with Helical Blade for a Submersible Well Pump and Method of Use

Abstract

An electrical submersible pump assembly has a pump, a motor and a seal section with a labyrinth chamber. A guide tube surrounds a drive shaft in the seal section and contains lubricant in fluid communication with lubricant in the motor. The guide tube has a guide tube port adjacent the downstream end of the labyrinth chamber. A. labyrinth tube has an open inlet end in the downstream end of the labyrinth chamber and an open outlet end near the upstream end of the labyrinth chamber. The labyrinth communicates well fluid on the exterior of the seal section into the labyrinth chamber in contact with the lubricant in the labyrinth chamber. A non rotating helical blade in the labyrinth chamber encircles the guide tube, defining a helical flow path between the outlet end of the labyrinth tube and the guide tube port of the guide tube.

1 . An electrical submersible pump assembly, comprising:
 a pump;   a motor cooperatively engaged with the pump for driving the pump;   a seal section having an axis and a labyrinth chamber between upstream and downstream ends of the seal section;   a guide tube extending along the axis between the upstream and downstream ends that contains lubricant in fluid communication with lubricant in the motor, the guide tube having an inlet port adjacent the downstream end to communicate the lubricant within the guide tube into the labyrinth chamber;   a labyrinth tube within the labyrinth chamber and having an open inlet end in the downstream end and an open outlet end within the labyrinth chamber adjacent the upstream end, the labyrinth tube adapted to communicate well fluid on the exterior of the seal section into the labyrinth chamber into contact with the lubricant in the labyrinth chamber to equalize a pressure of the lubricant with a pressure of the well fluid; and   a non rotating helical blade in the labyrinth chamber encircling the guide tube, defining a helical flow path between the outlet port of the labyrinth tube and the inlet port of the guide tube.   
     
     
         2 . The assembly according to  claim 1 , Wherein the labyrinth tube extends sealingly through turns of the helical blade. 
     
     
         3 . The assembly according to  claim 1 , further comprising:
 an inner sleeve surrounding the guide tube; and   wherein the helical blade has an inner diameter edge joined to the inner sleeve.   
     
     
         4 . The assembly according to  claim 1 , further comprising:
 an outer sleeve surrounding the helical blade, the outer sleeve having an outer diameter in contact with an inner diameter of the housing, the helical blade; and wherein   the helical blade has an outer edge in contact with an inner diameter of the outer sleeve.   
     
     
         5 . The assembly according to  claim 1 , wherein:
 the seal section has a housing; and   the helical blade has an outer edge in contact with an inner diameter of the housing.   
     
     
         6 . The assembly according to  claim 1 , further comprising:
 at least one baffle along the helical flow path and mounted between adjacent turns of the blade for retarding flow of well fluid along the helical flow path,   
     
     
         8 . The assembly according to  claim 1 , further comprising:
 at least one baffle along the helical flow path;   the baffle having an inner edge joined, to the guide tube;   the baffle having upstream and downstream edges joined to adjacent turns of the helical blade; and   the baffle having an outer edge located inward from an outer diameter of the helical blade, defining a gap for well fluid to pass from an upstream side of the baffle to a downstream side of the baffle along the helical flow path.   
     
     
         9 . An electrical submersible pump assembly, comprising:
 a pump;   a motor;   a seal section housing, having upstream and downstream connectors that connect the seal section into the assembly between the motor and the pump, defining a labyrinth chamber between the upstream and downstream end connectors;   a shaft driven by the motor and extending through the seal section into cooperative engagement with the pump;   a guide tube surrounding the shaft and extending between the upstream and downstream connectors, the guide tube defining an annular clearance between the guide tube and the shaft that contains lubricant in fluid communication with lubricant in the motor, the guide tube having a guide tube port adjacent the downstream connector to communicate the lubricant within the annular clearance into the labyrinth chamber;   a labyrinth tube within the labyrinth chamber parallel to and spaced outward from the guide tube and having an open inlet end in the downstream connector and an open outlet end in the labyrinth chamber near the upstream end connector, the labyrinth tube adapted to communicate well fluid on the exterior of the seal section into the labyrinth chamber into contact with the lubricant in the labyrinth chamber to equalize a pressure of the lubricant with a pressure of the well fluid; and   a non rotating helical blade in the labyrinth chamber encircling the guide tube, defining a helical flow path between the outlet end of the labyrinth tube and the guide tube port of the guide tube.   
     
     
         10 . The assembly according to  claim 9 , wherein the labyrinth tube extends sealingly through turns of the helical blade. 
     
     
         11 . The assembly according to  claim 9  further comprising:
 an inner sleeve surrounding the guide tube; 
 an inner sleeve port in registry with the guide tube port; and 
 wherein the helical blade has an inner diameter edge joined to the inner sleeve. 
 
     
     
         12 . The assembly according to  claim 9 , wherein:
 the labyrinth chamber has an inner diameter and an outer diameter; and   the helical blade has inner diameter substantially the same as the inner diameter of the labyrinth chamber and an outer diameter substantially the same as the outer diameter of the labyrinth chamber.   
     
     
         13 . The assembly according to  claim 9 , further comprising:
 an outer sleeve surrounding the helical blade, the outer sleeve having an outer diameter in contact with an inner diameter of the housing.   
     
     
         14 . The assembly according to  claim 9 , wherein the helical blade has an outer edge in contact with an inner diameter of the housing. 
     
     
         15 . The assembly according to  claim 9 , further comprising:
 at least one baffle along the flow path and mounted between adjacent turns of the blade for retarding flow of well fluid along the helical flow path.   
     
     
         16 . The assembly according to  claim 9 , further comprising:
 a plurality of baffles spaced along the helical flow path between adjacent turns of the blade for retarding flow of well fluid. along the helical flow path.   
     
     
         17 . The assembly according to  claim 9 , further comprising:
 at least one baffle along the helical flow path;   the baffle having an inner edge joined to the guide tube;   the baffle having upstream and downstream edges joined to adjacent turns of the helical blade; and   the baffle having an outer edge located inward from an outer diameter of the helical blade, defining a gap for well fluid to pass from an upstream side of the baffle to a downstream side of the baffle along the helical flow path.   
     
     
         18 . A method of pumping well fluid from a well with a submersible pump assembly having a pump, a motor cooperatively engaged with the pump for driving the pump, and a seal section with a labyrinth chamber between upstream and downstream ends of the seal section, the seal section having a guide tube extending between the upstream and downstream ends that has an inlet port adjacent the downstream end, the seal section having a labyrinth tube within the labyrinth chamber and having an open inlet end in the downstream end and an open outlet end within the labyrinth chamber adjacent the upstream end, the method comprising:
 mounting a non rotating helical blade in the labyrinth chamber around the guide tube, defining a helical flow path between the outlet port of the labyrinth tube and the inlet port of the guide tube;   flowing lubricant from the motor through the guide tube out the inlet port of the guide tube into the helical flow path in the labyrinth fluid chamber;   submersing the submersible pump assembly in well fluid in the well;   flowing well fluid through the labyrinth tube out the open outlet end into and along the helical flow path in contact with the lubricant to equalize a pressure of the lubricant within the motor with a pressure of well fluid exterior of the motor; and   driving the pump with the motor, causing the pump to pump well fluid from the well.   
     
     
         19 . The method according to  claim 18 , wherein:
 submersing the submersible pump assembly comprises installing the assembly within an inclined section of the well; and   flowing well fluid along the helical flow path requires the well fluid to flow upward above the guide tube, then back downward below the guide tube with each turn of the helical flow path.   
     
     
         20 . The method according to  claim 18 , further comprising:
 placing at least one baffle along the helical flow path; and   flowing well fluid along the helical flow path requires the well fluid to flow over the baffle.