The present patent application relates generally to a bearing system, and, more particularly to a load-limiting thrust bearing system used in an apparatus such as an electrical submersible pump (ESP).
In a hydrocarbon reservoir, a fluid-lifting apparatus is generally used for transferring a production fluid from a wellbore to a higher elevation on the surface of the ground. One such fluid-lifting apparatus includes an electrical submersible pump (ESP) having a pump, a motor, and a seal unit.
During operation of the ESP, impellers rotate within the pump for transferring the production fluid from the wellbore. Generally, the rotating impellers exert a thrust load on the ESP and such a thrust load is supported by a thrust bearing unit disposed within the ESP. The thrust bearing unit with a larger diameter, has a greater load bearing capacity. However, the wellbore has a size constraint which in turn restrains the diameter of the thrust bearing unit which can be used in the ESP, thereby affecting the load bearing capacity of the thrust bearing unit. In such a scenario, a backup thrust bearing unit may be used to enhance the load bearing capacity. However, existing bearing arrangements have not been sufficient to properly distribute and/or regulate the thrust load between the thrust bearing units, resulting in either overloading or uneven wear and tear of the thrust bearing unit.
Accordingly, there is a need for an improved bearing system and an associated method for distributing and regulating an axial thrust load between a plurality of thrust bearing units.
USPTO Backgrounds
USPTO Backgrounds