Seal Section Check Valve With Protection Tube

• US 20200133316A1
• Filed: 10/18/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: Baker Hughes, a GE Company, LLC (Baker Hughes Company)
• Inventors: Tanner, David, Semple, Ryan
• Granted Patent: US 10,928,841 B2
• Time in Patent Office: Days
• CPC Class Codes: E21B 43/128 Adaptation of pump systems with down-hole electric drives
• CPC Class Codes: F04D 13/086 the pump and drive motor are both submerged
• CPC Class Codes: F04D 13/10 adapted for use in mining bore holes
• CPC Class Codes: F04D 29/061 especially adapted for liquid pumps
• CPC Class Codes: F04D 29/086 especially adapted for liquid pumps
• CPC Class Codes: F04D 7/04 the fluids being viscous or non-homogenous
• CPC Class Codes: F16K 15/04 shaped as balls
• CPC Class Codes: G05D 16/0402 with two or more controllers mounted in series
• CPC Class Codes: G05D 16/06 the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule

Abstract

A submersible well pump assembly has a communication path for communicating motor lubricant to an interior of a pressure equalizer. A check valve passage with a check valve leads from the communication path to a pressure equalizing chamber. A dip tube has a dip tube inlet at the check valve passage below the check valve and a dip tube outlet in the pressure equalizing chamber. The dip tube is filled with motor lubricant to retard migration of well fluid from the pressure equalizing chamber into contact with the check valve.

Claims

1. A submersible well pump assembly for pumping well fluid, comprising:

a pump;

a motor that drives the pump, the motor being filled with a motor lubricant;

a housing having a longitudinal housing axis and operatively mounted to the motor;

an expandable and contractible pressure equalizer within the housing, defining a pressure equalizing chamber in the housing that surrounds an exterior of the pressure equalizer;

a motor lubricant communication path for communicating motor lubricant from the motor to an interior of the pressure equalizer;

a well fluid inlet port in the housing for admitting well fluid into the pressure equalizing chamber;

a check valve passage leading from the motor lubricant communication path to the pressure equalizing chamber;

a dip tube having a dip tube inlet at the check valve passage and extending from the check valve passage into the pressure equalizing chamber, the dip tube having a dip tube outlet at a lower elevation relative to the housing axis than the dip tube inlet; and

a check valve in the check valve passage at a higher elevation relative to the housing axis than the dip tube inlet and configured to expel motor lubricant from the motor lubricant communication path into the dip tube inlet when the pressure of the motor lubricant in the interior of the pressure equalizer is at a selected level above the pressure of the well fluid in the pressure equalizing chamber.

2. The assembly according to claim 1, wherein:

the dip tube is filled initially with motor lubricant prior to installing the assembly in a well.

3. The assembly according to claim 1, wherein:

the dip tube has at least one crest and at least one valley between the dip tube inlet and the dip tube outlet, the crest being at a higher elevation relative to the housing axis than the valley.

4. The assembly according to claim 1, wherein:

the dip tube has a plurality of crests, the crests being separated from each other by valleys of a lower elevation relative to the housing axis than the crests.

5. The assembly according to claim 1, wherein:

the dip tube extends at least partially around the housing axis and has a labyrinth passage between the dip tube inlet and the dip tube outlet, the labyrinth passage having upper portions that are at higher elevations relative to the housing axis than lower portions.

6. The assembly according to claim 1, wherein:

the dip tube extends more than half way around the longitudinal axis of the housing and has an undulating configuration between the dip tube inlet and the dip tube outlet.

7. The assembly according to claim 1, wherein:

the dip tube has a dip tube axis between the dip tube inlet and the dip tube outlet that is parallel to and offset from the housing axis.

8. The assembly according to claim 1, wherein:

the dip tube is a straight tubular member with a dip tube axis parallel to and offset from the housing axis; and

the dip tube outlet and the dip tube inlet are located on the dip tube axis.

9. The assembly according to claim 1, further comprising:

a guide tube extending through the housing along the housing axis;

a drive shaft extending through the guide tube;

wherein

the pressure equalizer comprises an elastomeric bag having a neck sealed to the guide tube, the neck defining a bag shoulder; and

the dip tube outlet is located at a higher elevation relative to the housing axis than the bag shoulder.

15. The assembly according to claim 1, wherein:

the pressure equalizer comprises an elastomeric bag having a neck sealed to the guide tube, the neck defining a bag shoulder facing the lower side of the pump end; and

the dip tube is located between the bag shoulder and the lower side of the housing.

10. A submersible well pump assembly for pumping well fluid, comprising:

a pump;

a motor that drives the pump, the motor being filled with a motor lubricant;

a housing having a longitudinal housing axis and mounted between the motor and the pump, the housing having pump end and a motor end;

a guide tube extending within the housing between the pump end and the motor end;

a shaft extending from the pump end to the motor end within the guide tube;

an expandable and contractible pressure equalizer surrounding the guide tube within the housing, defining a pressure equalizing chamber in the housing that surrounds an exterior of the pressure equalizer;

a motor lubricant communication path for communicating motor lubricant through the guide tube around the shaft from the motor to an interior of the pressure equalizer;

a well fluid inlet port in the housing for admitting well fluid into the pressure equalizing chamber;

a check valve passage in the pump end leading from the motor lubricant communication path to the pressure equalizing chamber, the check valve passage having a check valve passage outlet portion leading to a lower side of the pump end;

a check valve in the check valve passage outlet portion configured to expel motor lubricant from the motor lubricant communication path when the pressure of the motor lubricant in the interior of the pressure equalizer is at a selected level above the pressure of the well fluid in the pressure equalizing chamber;

a dip tube having a dip tube inlet at the check valve passage outlet portion below the check valve, the dip tube having a dip tube outlet in the pressure equalizing chamber below the lower side of the pump end; and

wherein

the dip tube is filled with motor lubricant to retard migration of well fluid from the pressure equalizing chamber into contact with the check valve.

11. The assembly according to claim 10, wherein:

the dip tube has at least one upward extending portion and one downward extending portion between the dip tube inlet and the dip tube outlet.

12. The assembly according to claim 10, wherein:

the dip tube has an undulating portion between the dip tube inlet and the dip tube outlet;

the undulating portion having at least one crest and at least one valley, the at least one crest being closer to the lower side of the pump end than the valley.

13. The assembly according to claim 10, wherein:

the dip tube extends at least partially around the housing axis and has a labyrinth passage between the dip tube inlet and the dip tube outlet, the labyrinth passage having upper portions that are closer to the lower side of the pump end than lower portions.

14. The assembly according to claim 10, wherein:

the dip tube has a dip tube axis extending through the dip tube inlet and the dip tube outlet, the dip tube axis being parallel to and laterally offset from the housing axis.

16. A method of retarding entry of well fluid into contact with a pressure equalizer motor lubricant check valve in a check valve passage of a pump end of a seal section of a submersible pump assembly, the seal section having a pressure equalizer that defines on its exterior a pressure equalizing chamber, the method comprising:

mounting a dip tube to the check valve passage such that the dip tube has a dip tube inlet below the check valve and a dip tube outlet in the pressure equalizing chamber below the pump end;

filling the pressure equalizer, the check valve passage, the pressure equalizing chamber and the dip tube with motor lubricant;

then

lowering the pump assembly into a well.

17. The method according to claim 16, wherein mounting the dip tube comprises:

providing the dip tube with an undulating configuration between the dip tube inlet and the dip tube outlet, the undulating configuration having at least one upper portion closer to the pump end than a lower portion.

18. The method according to claim 16, wherein mounting the dip tube comprises:

providing the dip tube with an undulating portion between the dip tube inlet and the dip tube outlet, the undulating configuration having upper and lower portions; and

extending the undulating at least partly around an axis of the seal section.

19. The method according to claim 16, wherein mounting the dip tube comprises placing the dip tube outlet directly below the dip tube inlet.

20. The method according to claim 16, further comprising:

after installing the pump assembly in the well, opening the check valve and expelling motor lubricant from the pressure equalizer through the dip tube in response to thermal expansion of the motor lubricant.