An improved electrical pump is first provided for use in a wellbore. The pump
comprises a stator and a stator housing, and an armature and an armature housing.
The stator housing and the armature housing define concentrically nested tubular
bodies. The armature housing is configured to permit production fluids to flow
therethrough. In one aspect, the stator and armature are assembled in connectible
and interchangeable sections called "modules" that can be attached in series. In
one aspect, the electrical operation of coils within the stator is protected from
individual coil short-circuiting or failure by wiring them in parallel, rather
than in series. In addition, each module may be wired in parallel. In this way,
a failure of one stator module will not result in the failure of another stator
module. In an embodiment of the present invention, the valves of the pump are capable
of being retrieved by a wireline, without pulling the entire production string.
A method for using a plurality of electrical pumps is also provided. The configuration
of the electrical pumps allows multiple linear pumps to be placed in series with
the production tubular member. Alternatively, a rotary pump design is provided
which allows multiple rotary pumps to be placed in series with the production tubular member.
