A critical component of the downhole system is the seal section, also commonly know as a motor seal, motor protector or equalizer. These units use modular construction which enables various configurations of multi-chamber seal sections. In addition to the primary function of transferring the motor torque to the pump, the seal section performs four primary functions. First, it equalizes the pressure in the wellbore with the pressure inside the motor; it provides area for motor oil expansion volume (induced by temperature changes in the motor); it isolates the well fluid from the clean motor oil; and it absorbs (or carries) the pump shaft thrust load and the load of the column of fluid above the unit.
The important major components are:
- Mechanical seals that prevent well fluid from traveling along the shaft into the next chamber.
- Mechanical seals are considered among the most critical components of the seal section.
- Elastomer bag(s) provide(s) expansion volume and isolation for clean motor oil.
- Labyrinth chamber(s) provide(s) expansion and isolation volume in horizontal or nearly horizontal wells.
- Thrust bearings carry the thrust load of the pump shaft and stages (fixed impeller type only).
- The thrust bearing is challenged by excessive thrust, vibration, misalignment and foreign material or foreign fluids like water from the well.
- Series diameters: 300, 400, 500
- Types: labyrinth chambers, elastomer bag
- Configurations: single, double, triple
- Options: abrasion resistant bearings, high load thrust bearings, corrosion resistant metallurgy