Oil Transport Structure in an Electric Motor of an Electric Submersible Pump (ESP) Assembly

An electric submersible pump (ESP) assembly, comprising:

• a production pump assembly;
• a seal section;
• and
• an electric motor comprising
• a drive shaft,
• a bearing coupled to the drive shaft;
• and
• a bushing having a cylindrical shape, wherein an inside surface of the bushing is in contact with an outside surface of the bearing and an outside surface of the bushing is retained by a housing of the electric motor or by a stator structure of the electric motor, and wherein the bushing defines at least one fluid flow channel extending from an upper edge of the bushing to a lower edge of the bushing and a middle portion of the at least one fluid flow channel is open to the inside surface of the bushing.

A method of lifting wellbore fluid to a surface, comprising:

• making-up an electric submersible pump (ESP) assembly at a surface location over the wellbore;
• running the ESP assembly into the wellbore at the lower end of a production tubing string;
• providing electrical power to an electric motor of the ESP assembly to cause the electric motor to turn, thereby turning a drive shaft of a seal section of the ESP assembly that is coupled to a drive shaft of the electric motor, thereby turning a drive shaft of a production pump assembly of the ESP assembly that is coupled to the drive shaft of the seal section;
• lifting wellbore fluid to the surface by the production pump assembly;
• and
• moving oil upwards in a bore of the drive shaft of the electric motor that is concentric with a longitudinal axis of the drive shaft of the electric motor, where the oil is moved by a fluid mover disposed within the bore.