Double Sealing Labyrinth Chamber for Use With a Downhole Electrical Submersible Pump

Abstract

A labyrinth seal assembly for an electrical submersible pumping system that communicates downhole pressure to a pump motor while sealing wellbore fluids from the motor. The labyrinth seal assembly includes a chamber circumscribing a pump shaft, labyrinth tubes, upper and lower shaft seals, and inner and outer guide tubes coaxially circumscribing the shaft. One labyrinth tube has an end in fluid communication with the wellbore fluid and another has an end in fluid communication with the pump motor. The labyrinth tubes extend into the chamber from opposite directions and each have an opening distal from where they enter the chamber. A port is provided in the inner guide tube distal from the upper shaft seal, and a port in the outer guide tube is provided proximate the upper shaft seal. Thus a labyrinth path is provided between the upper shaft seal and the chamber.

Description

BACKGROUND[0001]1. Field of Invention[0002]The present disclosure relates in general to submersible well pumps, and in particular to seal assemblies used in combination with the motors that drive submersible well pumps.[0003]2. Background of the Invention[0004]In oil wells and other similar applications in which the production of fluids is desired, a variety of fluid lifting systems have been used to pump the fluids to surface holding and processing facilities. It is common to employ various types of downhole pumping systems to pump the subterranean formation fluids to surface collection equipment for transport to processing locations. One such conventional pumping system is a submersible pumping assembly which is supported immersed in the fluids in the wellbore. The submersible pumping assembly includes a pump and a motor to drive the pump to pressurize and pass the fluid through production tubing to a surface location. A typical electrical submersible pump assembly (“ESP”) include...

AI Technical Summary

Benefits of technology

[0007]Disclosed herein is an electrical submersible pump assembly disposable within a wellbore. In one example, the electrical submersible pump assembly includes a motor, a pump coupled to the motor, a seal section housing between the pump and the motor, upper and lower guide members in the seal section housing, each having a central passage therethrough, defining a chamber in the seal section housing, an equalizing passage leading from the chamber to the motor, a shaft extending between the pump and the motor and through the central passages in the upper and lower guide members in the seal section housing, an upper seal between the passage of the upper guide member that seals around the shaft and seals well fluid from the chamber, and an inner labyrinth seal assembly circumscribing the shaft between the upper and lower guide members and comprising a looping flow path with an upper end in fluid communication with fluid in the central passage between the upper seal and an upper port in fluid communication with the chamber, so as to prevent well fluid that may leak past the upper seal from entering the pressure equalizing passage. An outer labyrinth seal assembly may be included with the electrical submersible pump assembly, where the outer labyrinth seal assembly has a looping flow path in the chamber with a first end in fluid commun...

Problems solved by technology

One hazard of high ESP housing pressure differentials is the wellbore fluid could breach seals and leak into the motor of the ESP.

Conventional seal sections have not proved completely effective in preventing environmental contamination of the motor.

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