Method and apparatus for testing for and removing trapped air from submersible well pump assembly

Patent metadata

Field	Value
Publication number	US-11525442-B2
Application number	US-202016877017-A
Country	US
Kind code	B2
Filing date	May 18, 2020
Priority date	May 18, 2020
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A fixture has a body that connects to a motor, the body having a bore. The body has a piston in the bore, separating the bore into a pressure chamber and a lubricant chamber in fluid communication with lubricant in the motor. A technician applies pressure to the pressure chamber, which causes the piston to increase pressure of the lubricant in the lubricant chamber and in the motor. The technician monitors a distance of movement of the piston, indicating a presence of residual air in the lubricant. If the movement meets a amount, the technician applies a vacuum to the lubricant chamber and bleeds out residual air from the lubricant in the motor.

First claim

The invention claimed is:

1. A method of determining whether residual air is present within lubricant in an electrical submersible pump motor, and removing the residual air if a sufficient amount is found, comprising:
connecting a fixture to an end of the motor, the fixture comprising:
a tubular body having a bore with a cap on an upper end and a lower end that is open to an interior of the motor;
a piston in the bore, the piston having a pressure side and a lubricant side, the lubricant side of the piston defining a lubricant chamber in the bore that is in fluid communication with the lubricant in the motor, the cap and the pressure side of the piston defining a pressure chamber in the bore;
an indicator rod attached to the piston and extending from the pressure side through the pressure chamber and sealingly through the cap;
a fluid line port in the piston extending from the pressure side to the lubricant side of the piston;
a flexible fluid line having an inlet connected to the fluid line port, the fluid line extending through the pressure chamber and the cap and having an outlet exterior of the body;
a sight glass included in the fluid line; and
a vacuum valve at the outlet of the fluid line;

the method further comprising:
applying fluid pressure to the pressure chamber, causing the piston to increase pressure of the lubricant in the lubricant chamber and in the motor; and
by observing the indicator rod, monitoring a distance of movement of the piston, if any, in response to the fluid pressure being applied, and if the distance meets a selected amount indicating an unacceptable presence of residual air in the lubricant, performing the following steps:
venting the fluid pressure in the pressure chamber; then
applying a vacuum to the outlet of the fluid line at a level sufficient to fill the fluid line with lubricant and draw an amount of lubricant into the sight glass;
monitoring the lubricant in the fluid line for residual air bubbles by observing the amount of lubricant in the sight glass; and
controlling the vacuum valve while the vacuum is being applied to cause the residual air bubbles in the fluid line to bleed out into the atmosphere.

2. The method according to claim 1 , wherein applying a vacuum and monitoring the lubricant in the fluid line further comprises:
connecting a sight glass line from the vacuum valve to a lower end of the sight glass;
connecting a vacuum line from a vacuum pump to an upper end of the sight glass;
operating the vacuum pump to suction lubricant from the lubricant chamber through the fluid line and the sight glass line into the sight glass while viewing the sight glass and controlling the vacuum valve to prevent lubricant that has entered the sight glass line from flowing to the vacuum pump but allowing residual air bubbles visible in the lubricant in the sight glass to bleed out to the vacuum pump.

3. The method according claim 2 , further comprising:
after causing the residual air bubbles to bleed out, again applying fluid pressure to the pressure chamber but to a lower level than the first application of fluid pressure; then
disconnecting the vacuum pump and the sight glass from the fixture; and
storing the motor while maintaining the fluid pressure in the pressure chamber at the lower level until the motor is to be installed in a well.

4. A method of determining whether residual air is present within lubricant in an electrical submersible pump motor, and removing the residual air if a sufficient amount is found, the method comprising:
monitoring a fixture coupled to an end of the motor, the fixture comprising:
a tubular body having a bore with a cap on an upper end and a lower end that is open to an interior of the motor;
a piston in the bore, the piston having a pressure side and a lubricant side, the lubricant side of the piston defining a lubricant chamber in the bore that is in fluid communication with the lubricant in the motor, the cap and the pressure side of the piston defining a pressure chamber in the bore;
an indicator rod attached to the piston and extending from the pressure side through the pressure chamber and sealingly through the cap;
a fluid line port in the piston extending from the pressure side to the lubricant side of the piston;
a flexible fluid line having an inlet connected to the fluid line port, the fluid line extending through the pressure chamber and the cap and having an outlet exterior of the body; and
a sight glass included in the fluid line;

identifying the presence of air in the lubricant based on monitoring an amount of movement of the indicator rod when the pressure chamber is pressurized;
purging the air from the lubricant by applying a vacuum at the outlet of the fluid line so that an amount of lubricant flows into the sight glass and air bubbles are visible in the amount of lubricant; and
removing the vacuum when air bubbles are not observed in the amount of lubricant in the sight glass.

5. The method of claim 4 , wherein removing the vacuum comprises closing a valve in the line that is disposed between the sight glass and the cap.

Assignees

• Baker Hughes Oilfield Operations Llc

Inventors

• Semple Ryan
• Meyer Aron
• Brunner Christopher

Classifications

• F04B53/18

  Lubricating · CPC title

• G01N33/2888 Primary

  Lubricating oil characteristics, e.g. deterioration (lubricating properties G01N33/30) · CPC title

• F04B9/1207

  using a source of partial vacuum or sub-atmospheric pressure · CPC title

• F04B51/00

  Testing machines, pumps, or pumping installations · CPC title

• F04B53/06 Primary

  Venting · CPC title