Pressure compensated motor power lead connection for submersible pump

Patent metadata

Field	Value
Publication number	US-10677033-B2
Application number	US-201815872174-A
Country	US
Kind code	B2
Filing date	Jan 16, 2018
Priority date	Jan 19, 2017
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A well pump electrical motor has a motor housing filled with a dielectric motor lubricant. A motor head has at least one motor lead passage in fluid communication with the motor lubricant. An outer seal, which is exposed to well fluid, seals around a motor lead in the motor lead passage. An inner seal seals around the motor lead in the motor lead passage inward from the outer seal and has an inner side in contact with the motor lubricant in the motor. A barrier fluid passage extends into an annular space between the inner and outer seals and contains a barrier fluid. A pressure compensating device has an inner side in contact with the barrier fluid in the barrier fluid passage for reducing a pressure differential between the barrier fluid and a hydrostatic fluid pressure of well fluid on the exterior of the motor.

First claim

The invention claimed is:

1. A well pump assembly, comprising:
an electrical motor for driving a pump, the motor having a motor housing filled with a dielectric motor lubricant;
a motor head on an end of the housing, the motor head having at least one motor lead passage extending from an interior of the housing to an exterior of the motor head, the motor lead passage being in fluid communication with the motor lubricant;
a motor lead extending from the exterior of the motor head into the motor lead passage, the motor lead comprising a metal tube containing an insulated conductor;
a motor wire extending from the interior of the housing into the motor lead passage and having an electrical connector in engagement with the conductor of the motor lead;
an outer seal sealing around the motor lead in the motor lead passage, the outer seal having an outer side adapted to be exposed to well fluid;
an inner seal sealing around the motor lead in the motor lead passage inward from the outer seal, the inner seal having an inner side in contact with the motor lubricant in the motor, the outer and inner seals defining between them an annular space in the motor lead passage;
the inner seal and the outer seal being outward from the electrical connector;
each of the outer and inner seals comprising a ferrule that forms a metal-to-metal sealing engagement between the metal tube and the motor lead passage;
a barrier fluid passage extending into the annular space and containing a barrier fluid that is in contact with an inner side of the outer seal and an outer side of the inner seal; and
a pressure compensating device having an inner side in contact with the barrier fluid in the barrier fluid passage for reducing a pressure differential between the barrier fluid and a hydrostatic fluid pressure of well fluid on the exterior of the motor.

2. The assembly according to claim 1 , further comprising:
a test port extending from the exterior of the motor head to a junction with the barrier fluid passage, the junction being between the pressure compensating device and the annular space; and
means for applying a test pressure to the test port and for blocking the test pressure from the pressure compensating device.

3. The assembly according to claim 2 , wherein the means for applying a test pressure comprises:
a test tool having a tubular stem that is insertable into the test port, the stem having a stem seal that seals between the stem and the barrier fluid passage at a point between the annular space and the junction, isolating a stem passage in the stem from the pressure compensating device.

4. The assembly according to claim 1 , wherein:
the at least one motor lead passage comprises a plurality of motor lead passages, and wherein the assembly further comprises:
a barrier fluid reservoir in the head;
a pressure equalizing chamber in the head, the pressure compensating device being mounted within the pressure equalizing chamber;
the barrier fluid passage having a plurality of first portions, each of the first portions extending from the annular space in one of the motor lead passages to the barrier fluid reservoir; and
the barrier fluid passage has a second portion extending from the barrier fluid reservoir to the pressure equalizing chamber.

5. The assembly according to claim 4 , wherein:
the barrier fluid reservoir is annular and concentric with a longitudinal axis of the head.

6. The assembly according to claim 4 , further comprising:
a test port extending from the exterior of the motor head through the second portion of the barrier fluid passage into the barrier fluid reservoir; and
a test tool having a tubular stem that is insertable into the test port and into sealing engagement with the barrier fluid reservoir, thereby communicating a stem passage in the stem to the barrier fluid reservoir and blocking the second portion of the barrier fluid passage from the stem passage.

7. The assembly according to claim 1 , wherein:
the barrier fluid passage has an inner end at a junction of the barrier fluid passage with the interior of the motor housing, the inner end of the barrier fluid passage having internal threads; and
the pressure compensating device comprises a metal bellows mounted in the inner end of the barrier fluid passage and having external threads that engage the internal threads.

8. The assembly according to claim 7 , wherein:
the inner end of the barrier fluid passage is open to the interior of the housing; and
the bellows separates the motor lubricant in the interior of the housing from the barrier fluid in the barrier fluid passage.

9. A well pump assembly, comprising:
an electrical motor for driving a pump, the motor having a motor housing filled with a dielectric motor lubricant;
a motor head on an end of the housing, the motor head having at least one motor lead passage extending from an interior of the housing to an exterior of the motor head, the motor lead passage being in fluid communication with the motor lubricant;
a motor lead extending from the exterior of the motor head into the motor lead passage;
an outer seal sealing around the motor lead in the motor lead passage, the outer seal having an outer side adapted to be exposed to well fluid;
an inner seal sealing around the motor lead in the motor lead passage inward from the outer seal, the inner seal having an inner side in contact with the motor lubricant in the motor, the outer and inner seals defining between them an annular space in the motor lead passage;
a barrier fluid passage extending into the annular space and containing a barrier fluid that is in contact with an inner side of the outer seal and an outer side of the inner seal;
a pressure compensating device having an inner side in contact with the barrier fluid in the barrier fluid passage for reducing a pressure differential between the barrier fluid and a hydrostatic fluid pressure of well fluid on the exterior of the motor; wherein:
the motor lead comprises a metal tube containing an insulated conductor;
each of the outer and inner seals comprises a ferrule that forms a metal-to-metal sealing engagement between the metal tube and the motor lead passage;
a spacer ring is located in the annular space between the outer and inner seals, the spacer ring being in non-sealing engagement with the motor lead passage; and
a nut is at an entrance of the motor lead passage, the nut, when rotated, exerting an inward directed force against outer seal, through the spacer ring to the inner seal to deform the ferrules of the outer and inner seals into sealing and retaining engagement with the motor lead passage.

10. A well pump assembly, comprising:
a pump;
an electrical motor cooperatively connected with the pump for driving the pump, the motor having a motor housing filled with a dielectric motor lubricant;
a motor head on an end of the housing, the motor head having a longitudinal axis;
three motor lead passages spaced around the axis, each having an open lower end in fluid communication with the motor lubricant in the housing;
three motor leads, each extending from an exterior of the motor head into one of the motor lead passages;
three upper seals, each sealing around one of the motor leads in one of the motor lead passages, each of the upper seals having an upper side adapted to be exposed to well fluid;
three lower seals, each sealing around one of the motor leads in one of the motor lead passages below one of the upper seals, each of the lower seals having a lower side in contact with the motor lubricant in the housing, the upper and lower seals in each of the motor lead passages defining between them an annular space in each of the motor lead passage;

Assignees

• Baker Hughes A Ge Co Llc

Inventors

• Semple Ryan P
• Tanner David

Classifications

• H02K5/132

  Submersible electric motors (H02K5/128 takes precedence) · CPC title

• E21B33/1208

  characterised by the construction of the sealing or packing means (E21B33/1277 takes precedence) · CPC title

• H02K2205/09

  Machines characterised by drain passages or by venting, breathing or pressure compensating means · CPC title

• E21B43/128 Primary

  Adaptation of pump systems with down-hole electric drives · CPC title