Bidirectional piston seals with pressure compensation

A system for accommodating the expansion of motor lubricant in a motor within an electric submersible pump used for removing fluids from a wellbore, the system comprising:

• a seal section connected to a first end of the motor;
• and
• a fluid expansion module connected to a second end of the motor, wherein the fluid expansion module has a longitudinal axis and wherein the fluid expansion module comprises at least one piston assembly, wherein the at least one piston assembly moves along the longitudinal axis of the fluid expansion module in response to an expansion of the motor lubricant, wherein the at least one piston assembly comprises:
• a piston body having an exterior surface;
• a plurality of seals connected to the exterior surface of the piston body, wherein a space between the plurality of seals creates an annular space;
• and
• a pressure equalization system, wherein the pressure equalization system reduces a pressure differential between fluid in the annular space and fluid surrounding the at least one piston assembly.

A fluid expansion module for use in an electric submersible pumping system that includes a pump driven by a fluid-filled motor, the fluid expansion module comprising:

• a piston seal housing in fluid communication with the fluid-filled motor;
• and
• a first piston assembly contained within the piston seal housing, wherein the first piston assembly comprises:
• a piston body having an exterior surface;
• a plurality of seals connected to the exterior surface of the piston body, wherein a space between the plurality of seals creates an annular space;
• and
• a pressure equalization system, wherein the pressure equalization system reduces a pressure differential between fluid in the annular space and fluid in the piston seal housing.