Electrical submersible pump assembly for separating gas and oil

Patent metadata

Field	Value
Publication number	US-10107274-B2
Application number	US-201313852699-A
Country	US
Kind code	B2
Filing date	Mar 28, 2013
Priority date	Apr 2, 2012
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

An electrical submersible pump assembly for use in a well, including a well having a high gas-to-liquid ratio has a motor, a hollow, tubular drive shaft which drives the pump, and a liquid-gas separator assembly upstream of the pump intake. The liquid-gas separator has a hollow tubular portion, which communicates with the open, lower end of the drive shaft, openings through its sidewall, and a closed lower end. The sidewall also includes at least one outwardly extending projection shaped for urging liquid contained in a liquid/gas mixture flowing towards the pump outwardly, away from the sidewall openings. Preferably, the outwardly extending projection comprises a helical blade which, using either the well casing or a separate sheath, defines a helical channel through which the oil-gas mixture flows prior to reaching the pump intake. The centrifugal force in the channel forces the oil component away from the openings and forces the gas component through the openings, where such gas may be vented to the surface.

First claim

The invention claimed is:

1. An electrical submersible pump assembly for use in a well comprising:
an electric motor;
a pump having an intake and an outlet;
a drive shaft configured to be driven by said motor and to drive said pump, said drive shaft having a central axis, a hollow interior, and open upper and lower shaft ends;
a liquid-gas separator assembly having a stationary tubular portion with a hollow interior communicating with the open, lower end of said drive shaft; wherein said stationary tubular portion includes a sidewall portion having openings therethrough and wherein said stationary tubular portion includes a closed, lower end; wherein said sidewall portion includes at least one outwardly extending projection shaped for urging liquid contained in a liquid/gas mixture which is flowing towards said pump intake away from said openings and cause gas contained in the liquid/gas mixture to flow through the openings into the hollow interior of said stationary tubular portion and, thereafter, to flow outwardly from said stationary tubular portion through the open lower end of the drive shaft into the drive shaft interior, wherein said at least one outwardly extending projection comprises at least one blade which wraps spirally about said sidewall portion, at least several turns, to cause liquid and gas drawn towards said pump to travel in a spiral path, wherein said openings are located on the sidewall portion between said turns such that liquid is separated from gas prior to liquid reaching the pump intake, and wherein said at least one helical blade is secured to said sidewall portion; and
a bearing means for supporting said drive shaft so that said drive shaft rotates relative to said stationary tubular portion.

2. The pump assembly of claim 1 , wherein said blade comprises a helical blade which extends spirally about said sidewall portion to cause liquid drawn towards said pump to travel in a helical path.

3. The pump assembly of claim 1 for use in a well casing, wherein said blade has an outer edge sized to fit tightly within the well casing, and an inner edge fitting tightly about said sidewall portion, wherein said blade and said stationary tubular portion, when installed in the well casing, form a helical channel through which gas and oil in the well must flow before reaching said pump intake.

4. The pump assembly of claim 1 , wherein said blade has an inner edge fitting tightly about said sidewall portion, and wherein said liquid-gas separator assembly further comprises a hollow, cylindrical sheath surrounding the outside edge of said blade such that said blade, sheath, and sidewall portion form a helical channel through which gas and oil in the well must flow before reaching said pump intake.

5. The electrical submersible pump assembly of claim 1 , further comprising stationary tubing connected to communicate with the upper end of the drive shaft which extends from said motor out of the well, so that gas and liquid exit from the well separately.

6. The pump assembly of claim 1 , wherein said electric motor is located downstream of said pump and adjacent thereto, said drive shaft extends through a motor housing and a pump housing to provide a hollow passage through said housing, and said stationary tubular portion extends downwardly from said lower end of said drive shaft and has an upper end secured to said lower end of said drive shaft by said coupling means.

7. The pump assembly of claim 6 , wherein said coupling means comprises bearing means.

8. An electrical submersible pump assembly for use in a well, comprising:
a pump having an intake and an outlet;
an electric motor located adjacent to said pump;
a hollow drive shaft for driving said pump and driven by said electrical motor, said drive shaft having a central axis, a hollow interior, and open upper and lower shaft ends; and
a liquid-gas separator assembly having a stationary tubular portion with a hollow interior communicating with the open, lower end of said drive shaft, wherein said stationary tubular portion includes a sidewall portion having openings therethrough to allow gas in the well to flow into a hollow interior thereof, wherein said stationary tubular portion includes a closed, lower end; and wherein said sidewall portion includes at least one outwardly extending projection shaped for urging liquid contained in a liquid/gas mixture which is flowing towards said pump intake away from said openings and cause gas contained in the liquid/gas mixture to flow through the openings into the hollow interior of said stationary tubular portion, where said gas thereafter flows outwardly from said stationary tubular portion through the open lower end of the drive shaft into the drive shaft interior, wherein said at least one outwardly extending projection comprises a single blade which wraps spirally about said sidewall portion forming, at least several turns, to cause liquid and gas drawn towards said pump to travel in a spiral path, and wherein said openings are located on the sidewall between said at least several turns such that liquid is separated from gas prior to the liquid reaching the pump intake.

9. The pump assembly of claim 8 , wherein said drive shaft extends through said motor housing and pump housing to provide a hollow passage through said housings.

10. The pump assembly of claim 8 , wherein said blade comprises a helical blade which extends spirally about said sidewall portion to cause liquid drawn towards said pump to travel in a helical path.

11. The pump assembly of claim 8 , wherein the well has a well casing, and wherein said blade has an outer edge sized to fit tightly within the well casing, and an inner edge fitting tightly about said sidewall portion, wherein said blade and said stationary tubular portion, when installed in the well casing, form a helical channel through which gas and oil in the well must flow before reaching said pump intake.

12. The pump assembly of claim 8 , wherein said blade has an inner edge fitting tightly about said sidewall portion, and wherein said liquid-gas separator assembly further comprises a hollow, cylindrical sheath surrounding the outside edge of said blade such that said blade, sheath, and sidewall portion form a helical channel through which gas and oil in the well must flow before reaching said pump intake.

13. The electrical submersible pump assembly of claim 8 , further comprising stationary tubing connected to communicate with the upper end of the drive shaft which extends from said motor out of the well, so that gas and liquid exit from the well separately.

Assignees

• Saudi Arabian Oil Co

Inventors

• Noui-Mehidi Mohamed Nabil
• Ahyad Rabea

Classifications

• F04B47/06

  having motor-pump units situated at great depth · CPC title

• F04B17/03 Primary

  driven by electric motors · CPC title

• E21B43/38

  in the well · CPC title

• E21B43/128 Primary

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