Electrical submersible pump

Abstract

A method and apparatus for lifting fluids from a well is provided. In one embodiment, a pump assembly comprises a rotary motor adapted to actuate a reciprocating pump. The motor shaft of the rotary motor is threadedly coupled to a drive member of the reciprocating pump. In operation, rotation of the rotary motor causes reciprocation of the reciprocating pump.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]Embodiments of the present invention generally relate to a pumping apparatus for transporting fluids from a well formation to the earth's surface. Particularly, embodiments of the present invention relate to an electrical submersible pump assembly having a positive displacement pump driven by a rotary motor. More particularly, embodiments of the present invention relate to a pump assembly having a rotary motor capable of rotating in two directions.[0003]2. Description of the Related Art[0004]Many hydrocarbon wells are unable to produce at commercially viable levels without assistance in lifting formation fluids to the earth's surface. In some instances, high fluid viscosity inhibits fluid flow to the surface. More commonly, formation pressure is inadequate to drive fluids upward in the wellbore. In the case of deeper wells, extraordinary hydrostatic head acts downwardly against the formation, thereby inhibiting the unas...

AI Technical Summary

Benefits of technology

[0019]In another embodiment still, a pump assembly comprises a pump adapted to pump a fluid between at least two fluid cavities and a rotary motor adapted to actuate the pump, wherein a direction of fluid flow between the at least two fluid cavities is reversed by changing a rotational direction of the rotary motor. In yet another embodiment, each of the fluid cavities is expandable. In yet another embodiment, expansion or retraction of the fluid cavity controls movement of a pumped fluid in the chamber.

Problems solved by technology

Many hydrocarbon wells are unable to produce at commercially viable levels without assistance in lifting formation fluids to the earth's surface.

More commonly, formation pressure is inadequate to drive fluids upward in the wellbore.

The rise of the liquid level in the casing leads to a pressure increase of the liquid in the casing, which may shut off the flow of gas unless the liquid is removed.

Submersible pump assemblies which utilize a linear electric motor face many challenges during their employment.

A first problem relates to the introduction of the submersible pump into the wellbore.

At the same time, submersible pumps can be of such a length that it becomes difficult for the pump to negotiate turns and bends within the tubing string of the well.

Another problem inherent in current submersible pump designs pertains to the restricted diameter for fluid flow within the motor section.

The result is that fluid being displaced by the pump must travel through restrictive fluid ports which reside within the armature portion of the motor en route to the surface.

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