Electrical submersible pump lubricant and coolant

A method for producing hydrocarbons from a subterranean well, the method including:

• providing an electrical submersible pump assembly with a motor, a seal section, and a pump, where the motor has:
• a motor housing, the motor housing being an elongated member;
• a stator located within the motor housing, the stator having a stator body with an interior cavity extending along a central axis of the stator;
• a rotor assembly located within the interior cavity of the stator, the rotor assembly including a rotor shaft, a rotor member, and an intermediate rotor bearing assembly, where the rotor member and the intermediate rotor bearing assembly circumscribe the rotor shaft, and where the rotor shaft is an elongated member that extends along the central axis of the stator;
• a liner located along an interior surface of the interior cavity, the liner being a thin walled member that is secured to the motor housing and seals the stator body from a wellbore fluid;
• a rotor cavity located within an inner bore of the liner;
• a membrane located within the liner;
• filling the rotor cavity with a hydrophobic fluid that comprises magnetic particles that are encapsulated within a polymer to prevent agglomeration of the particles;
• lowering the electrical submersible pump assembly into the subterranean well with a deployment string;
• and
• operating the electrical submersible pump assembly to lift production fluids in a direction out of the subterranean well and circulate the hydrophobic fluid within the rotor cavity;
• and
• wherein the liner forms a hermetically sealed space around the stator and is a barrier to fluid communication between the hermetically sealed space and the interior cavity, and dielectric fluid in the hermetically sealed space is different from the hydrophobic fluid in the rotor cavity.

A method for producing hydrocarbons from a subterranean well, the method including:

• forming a rotor assembly by positioning an intermediate rotor bearing assembly and a rotor member onto a rotor shaft so that the rotor member and the intermediate rotor bearing assembly circumscribe the rotor shaft, where the rotor shaft is an elongated member;
• pulling the rotor assembly into an interior cavity of a stator body within a motor housing, the motor housing being an elongated member and the stator body being part of a stator, where:
• the rotor shaft extends along a central axis of the stator;
• a liner is located along an interior surface of the interior cavity, the liner being a thin walled member that is secured to the motor housing and that hermetically seals dielectric fluid in contract with the stator body from the rotor assembly;
• a rotor cavity is located within an inner bore of the liner;
• a membrane is located within the liner;
• a hydrophobic fluid comprising magnetic particles is circulating within the rotor cavity, the hydrophobic fluid being different and separate from the dielectric fluid;
• and where
• the motor housing, the stator, the rotor assembly, and the liner form a motor;
• forming an electrical submersible pump assembly with the motor, a seal section, and a pump;
• lowering the electrical submersible pump assembly into the subterranean well with a deployment string;
• and
• operating the electrical submersible pump assembly to lift production fluids in a direction out of the subterranean well.