Gas-lock re-prime shaft passage in submersible well pump and method of re-priming the pump

Patent metadata

Field	Value
Publication number	US-11268516-B2
Application number	US-201916678105-A
Country	US
Kind code	B2
Filing date	Nov 8, 2019
Priority date	Nov 19, 2018
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A well fluid centrifugal pump has a shaft passage in the shaft. The shaft passage has an open upper end above the impellers and a closed lower end below the impellers. An outlet port extends laterally from the shaft passage. A gas-lock re-priming device in the shaft passage diverts a portion of well fluid in the discharge adapter bore through the shaft passage and out the outlet port. The re-priming device may be a pressure actuated valve that is biased to a closed position and opens when the pressure in the discharge adapter bore drops below a minimum. Alternately, the re-priming device may be an orifice member with an orifice passage that continuously diverts a portion of the well fluid in the discharge adapter bore out the outlet port.

First claim

The invention claimed is:

1. An apparatus for pumping well fluid from a well, comprising:
a centrifugal pump assembly having a shaft, impellers mounted to the shaft for rotation therewith, an intake at a second end of the pump assembly, and a discharge adapter at a first end of the pump assembly into which well fluid discharged by the impellers flows;
a shaft passage extending into the shaft along a longitudinal axis of the pump assembly, the shaft passage having a first end in fluid communication with well fluid in the discharge adapter;
at least one outlet port extending laterally from the shaft passage to an inlet of at least one of the impellers; and
a gas-lock re-priming device in the shaft passage for diverting a portion of well fluid in the discharge adapter through the shaft passage and out the outlet port.

2. The apparatus according to claim 1 , wherein at least one of the outlet ports is adjacent the inlet of the impeller closest to the intake.

3. The apparatus according to claim 1 , wherein the re-priming device is located in the shaft passage closer to the discharge adapter than any of the impellers.

4. The apparatus according to claim 2 , wherein another one of the outlet ports is at an inlet of another one of the impellers.

5. The apparatus according to claim 1 , wherein:
the pump assembly comprises a first pump connected in tandem to a second pump;
the shaft comprises a first shaft section in the first pump, a second shaft section in the second pump, and a coupling connecting the first shaft section to the second shaft section;
the shaft passage extends through the first shaft section into the second shaft section; and
the outlet port is located adjacent an inlet of one of the impellers in the second pump.

6. The apparatus according to claim 5 , further comprising:
a seal member in the shaft passage at a second end of the first shaft section and a first end of the second shaft section, the seal member sealing a junction between the shaft passage in the first shaft section with the shaft passage in the second shaft section.

7. The apparatus according to claim 1 , wherein the shaft passage has a second end that is closed.

8. The apparatus according to claim 1 , wherein the re-priming device comprises:
a pressure controlled valve in the shaft passage that is configured to close if a discharge pressure of well fluid in the discharge adapter is above a selected level, blocking flow through the shaft passage, and to open if the discharge pressure is below the selected level.

9. The apparatus according to claim 1 , wherein the re-priming device comprises:
a valve seat;
an axially movable valve element relative to the shaft; and
a spring that biases the valve element away from the seat.

10. The apparatus according to claim 1 , wherein the re-priming device comprises:
a valve seat;
a valve element positioned closer to the first end of the shaft than the valve seat; and
a spring that urges the valve element away from the valve seat.

11. The apparatus according to claim 8 , wherein the pressure control valve comprises:
a retainer secured in the shaft passage, slots formed through the retainer, a valve seat in the shaft passage disposed between the retainer and the outlet port, an orifice formed through the valve seat, a valve element coupled to and biased towards the retainer, so that when pressure in the slots exceeds pressure at the outlet, the valve element lands in the orifice to block communication between the slots and the outlet port.

12. An apparatus for pumping well fluid from a well, comprising:
a centrifugal pump assembly having a shaft with a longitudinal axis, impellers mounted to the shaft for rotation therewith, a discharge adapter at an upper end of the pump assembly with a discharge adapter bore into which well fluid discharged by the impellers flows;
a shaft passage in the shaft, the shaft passage having an open upper end above the impellers and a closed lower end below the impellers;
at least one outlet port extending laterally from the shaft passage below the impellers; and
a gas-lock re-priming device in the shaft passage for diverting a portion of well fluid in the discharge adapter bore through the shaft passage and out the outlet port.

13. The apparatus according to claim 12 , wherein another one of the outlet ports is above said first mentioned outlet port and at an inlet of another one of the impellers.

14. The apparatus according to claim 12 , wherein:
the pump assembly comprises an upper pump connected in tandem to a lower pump;
the shaft comprises an upper shaft section in the upper pump, a lower shaft section in the lower pump, and a coupling connecting the upper shaft section to the lower shaft section;
a seal member seals a portion of the shaft passage in the upper shaft section to a portion of the shaft passage in the lower shaft section; and
the at least one outlet port is located adjacent an inlet of one of the impellers in the lower pump.

15. The apparatus according to claim 12 , wherein the re-priming device comprises:
a pressure controlled valve in the shaft passage that is closed if a discharge pressure of the well fluid in the discharge adapter bore is above a selected level and open if the discharge pressure is in the discharge adapter bore is below the selected level.

16. The apparatus according to claim 12 , wherein the re-priming device comprises:
a valve seat;
an axially movable valve element; and
a spring that biases the valve element away from the seat.

17. The apparatus according to claim 12 , wherein the re-priming device comprises:
an orifice member in the shaft passage, the orifice member having an orifice passage for continuously diverting a selected portion of the well fluid in the discharge adapter through the shaft passage and out the outlet port.

18. A method for pumping well fluid from a well with a centrifugal pump assembly having a shaft, impellers mounted to the shaft for rotation therewith, and a discharge adapter at a first end of the pump assembly into which well fluid discharged by the impellers flows, the method comprising;
providing the shaft with a shaft passage along a longitudinal axis of the pump assembly and at least one outlet port extending laterally from the shaft passage to an inlet of at least one of the impellers;
installing in the shaft passage a gas-lock re-priming device; and
diverting a portion of well fluid in the discharge adapter through the shaft passage and out the outlet port.

19. The method according to claim 18 , wherein:
installing a gas-lock re-priming device comprises installing a valve in the shaft passage that is biased to a closed position; and
diverting a portion of the well fluid comprises moving the valve to an open position in response to a drop in pressure of the well fluid in the discharge adapter below a selected level.

20. The method according to claim 18 , wherein:
installing a gas-lock re-priming device comprises inserting an orifice member with an orifice passage into the shaft passage; and
diverting a portion of the well fluid comprises continuously recirculating a portion of the well fluid through the shaft passage and out the outlet port.

Assignees

• Baker Hughes A Ge Co Llc
• Baker Hughes Holdings Llc

Inventors

• Lu Xiaonan
• Rutter Risa
• Ye Zheng

Classifications

• F05D2240/61

  Hollow · CPC title

• F04D13/10

  adapted for use in mining bore holes · CPC title

• F04D9/02

  Self-priming pumps · CPC title

• F04D1/06

  Multi-stage pumps (F04D1/02, F04D13/10 take precedence) · CPC title

• F04D9/008 Primary

  by means in the suction mouth, e.g. foot valves · CPC title