Smooth-starting electrical submersible pumps
AssigneeSaudi Arabian Oil Company
InventorsHazza G. Al-Otaibi, Sultan S. Alotaibi
Life of this patent
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Abstract
An electrical submersible pump system for preventing high-pressure drawdown while starting includes a fixed-speed drive, hermetically-sealed motor including a motor shaft extending therefrom, a discharge pump including a pump shaft extending therefrom, and a torque converter interposing the motor and the pump. The torque converter includes a hollow body filled with a conversion fluid, a motor-side rotor mated to an end of the motor shaft and operable generate a vortex of the conversion fluid within the hollow body when the motor shaft is provided with a torque, and a pump-side rotor mated to an end of the pump shaft and rotatable as the vortex impinges on the pump-side rotor, and thereby providing a torque to the pump shaft to operate the discharge pump.
Claims17
An electrical submersible pump system for preventing high-pressure drawdown while starting, the electrical submersible pump system comprising:
- a fixed-speed drive, hermetically-sealed motor including a motor shaft extending therefrom;
- a discharge pump including a pump shaft extending therefrom;
- and
- a torque converter interposing the motor and the pump and including:
- a hollow body filled with a conversion fluid;
- a motor-side rotor mated to an end of the motor shaft and operable to generate a vortex of the conversion fluid within the hollow body when the motor shaft is provided with a torque;
- a pump-side rotor mated to an end of the pump shaft and rotatable as the vortex impinges on the pump-side rotor, and thereby providing a torque to the pump shaft to operate the discharge pump;
- a plurality of shaft apertures defined in the hollow body and sized to receive the motor shaft and the pump shaft;
- a primary seal interposing the torque converter and the discharge pump, the primary seal being operable to prevent fluid flow between the torque converter and the discharge pump;
- and
- a secondary seal interposing the torque converter and the motor, the secondary seal being operable to prevent fluid flow between the torque converter and the motor,
- wherein the primary seal provides a housing for the pump shaft and extends from the pump to the torque converter.
A method of starting an electrical submersible pump system disposed in a wellbore, the method comprising:
- activating a hermetically-sealed motor including a motor shaft extending therefrom and thereby rotating the motor shaft;
- providing a torque to a motor-side rotor via the motor shaft, the motor-side rotor being arranged within a body of a torque converter defining a plurality of shaft apertures sized to receive the motor shaft and a pump shaft;
- preventing fluid flow across the shaft apertures via a primary seal interposing the torque converter and the discharge pump and a secondary seal interposing the torque converter and the motor, the secondary seal providing a housing for the motor shaft and extending from the motor to the torque converter;
- generating a vortex of a conversion fluid housed within the torque converter as the motor-side rotor rotates;
- impinging the vortex on a pump-side rotor arranged within the torque converter and thereby rotating the pump-side rotor to transfer a portion of the torque from the motor-side rotor to the pump-side rotor;
- transferring a portion of the torque from the motor-side rotor to a pump-side rotor included in an upper end of the torque converter through the rotation of the conversion fluid;
- and
- actuating, via the pump shaft operatively coupled to the pump-side rotor, a discharge pump as the pump-side rotor rotates, and thereby pumping a formation fluid through the electrical submersible pump system.
Dependencies are inferred from the claim text.