Seal configuration for high density lubrication oils

Patent metadata

Field	Value
Publication number	US-12595805-B2
Application number	US-202318234807-A
Country	US
Kind code	B2
Filing date	Aug 16, 2023
Priority date	Aug 16, 2022
Publication date	Apr 7, 2026
Grant date	Apr 7, 2026

Abstract

A seal section for use in a downhole submersible pumping system includes a lower chamber, an upper chamber and an intermediate guide section between the lower chamber and the upper chamber. The lower chamber includes a seal bag assembly that has a seal bag containing motor oil and an exterior space around the seal bag that contains high density oil that is denser than the motor oil. The upper chamber includes a volume of the high density oil at the bottom of the upper chamber and a gravity trap connected to the exterior space through an intermediate passage in the intermediate guide section. The gravity trap includes an opening submerged in the volume of high density oil in the upper chamber.

First claim

What is claimed is:

1 . A seal section for use in a downhole submersible pumping system, the seal section comprising:
a lower chamber, wherein the lower chamber comprises:
a seal bag assembly that comprises a seal bag that contains motor oil; and
an exterior space around the seal bag that contains high density oil that is denser than the motor oil;
an intermediate guide section above the lower chamber, wherein the intermediate guide section includes an intermediate passage in fluid communication with the exterior space surrounding the seal bag; and an upper chamber above the intermediate guide section, wherein the upper chamber comprises:
a volume of the high density oil at the bottom of the upper chamber; and
a gravity trap, wherein the gravity trap comprises:
a first end connected to the intermediate passage;
a second end with an opening submerged in the volume of high density oil in the upper chamber; and
a central section between the first end and the second end, wherein the central section is above the opening of the second end.

2 . The seal section of claim 1 , wherein the high density oil is selected from the group consisting of PFPE (perfluoropolyether), HFE (hydrofluorother), PFC (perfluorocarbon), PF Polymer (polyfluorene polymer), FK (fluoroketone), PF Alcene (polyfluorene alcene), and Perfluoro methyl pentene.

3 . The seal section of claim 1 , wherein the seal bag assembly further comprises:
a bag support tube; and an inner annular space between the bag support tube and a shaft passing through the bag support tube.

4 . The seal section of claim 3 , wherein the intermediate guide section comprises a return port connected between the inner annular space and the exterior space surrounding the seal bag.

5 . The seal section of claim 1 further comprising:
an end module connected to a lower end of the lower chamber; and
a head connected to an upper end of the upper chamber.

6 . The seal section of claim 5 , wherein the head comprises:
an upper head shaft seal; a lower head shaft seal; and a positive pressure chamber disposed between the upper head shaft seal and the lower head shaft seal.

7 . The seal section of claim 6 , wherein the head further comprises a positive pressure module that applies a pressure to fluid inside the positive pressure chamber.

8 . The seal section of claim 7 , wherein the fluid inside the positive pressure chamber is high density oil.

9 . A seal section for use in a downhole submersible pumping system deployable in a wellbore, the seal section comprising:
a lower chamber, wherein the lower chamber comprises:
a first separation mechanism; and
an exterior space around the first separation mechanism that contains high density oil that is denser than motor oil;
an intermediate guide section above the lower chamber, wherein the intermediate guide section includes an intermediate passage in fluid communication with the exterior space surrounding the first separation mechanism; and an upper chamber above the intermediate guide section, wherein the upper chamber comprises:
a volume of the high density oil at the bottom of the upper chamber; and
a gravity trap, wherein the gravity-trap comprises:
a first end connected to the intermediate passage;
a second end with an opening submerged in the volume of high density oil in the upper chamber; and
a central section between the first end and the second end, wherein the central section is above the opening of the second end.

10 . The seal section of claim 9 , wherein the first separation mechanism is a seal bag assembly.

11 . The seal section of claim 10 , wherein the seal bag assembly comprises a seal bag that includes a seal bag interior space.

12 . The seal section of claim 11 , wherein the seal bag interior space is filled with a motor oil.

13 . The seal section of claim 12 , wherein the motor oil has a density of less than 1 kg/liter.

14 . The seal section of claim 10 , wherein the first separation mechanism is a multifluid labyrinth system that comprises:
a labyrinth lower volume of a high density oil; and a labyrinth upper volume above the labyrinth lower volume, wherein the labyrinth upper volume comprises lighter density oil.

15 . The seal section of claim 10 , wherein the first separation mechanism is selected from the group consisting of piston-based separation mechanisms and metal bellows-based separation mechanisms.

16 . A downhole pumping system useable for recovering fluids from a wellbore, the pumping system comprising:
a motor; a pump driven by the motor; and a seal section between the pump and the motor, wherein the seal section comprises:
a lower chamber, wherein the lower chamber comprises:
a seal bag assembly that comprises a seal bag that contains motor oil; and
an exterior space around the seal bag that contains high density oil that is denser than the motor oil; and

an upper chamber above the lower chamber, wherein the upper chamber comprises:
a volume of the high density oil at the bottom of the upper chamber; and
a gravity trap, wherein the gravity-trap comprises:
a first end in fluid communication with the high density oil in the exterior space around the seal bag;
a second end with an opening submerged in the volume of high density oil in the upper chamber; and
a central section between the first end and the second end, wherein the central section is above the opening of the second end.

17 . The pumping system of claim 16 , wherein the seal section further comprises an intermediate guide section between the upper chamber and the lower chamber, and wherein the intermediate guide section comprises an intermediate passage that places the volume of high density oil at the bottom of the upper chamber in fluid communication with the high density oil in the exterior space around the seal bag in the lower chamber through the gravity trap.

18 . The pumping system of claim 17 , wherein the seal section further comprises a shaft that transmits torque from the motor to the pump.

Assignees

• Baker Hughes Oilfield Operations Llc

Inventors

• Collins Charles
• Semple Ryan
• Meyer Aron
• Tanner David

Classifications

• F04D13/10 Primary

  adapted for use in mining bore holes · CPC title

• F04D29/061

  especially adapted for liquid pumps · CPC title

• E21B43/128

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

• F04D29/108

  the sealing fluid being other than the working liquid or being the working liquid treated · CPC title

• F04D29/086 Primary

  especially adapted for liquid pumps · CPC title