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Maintenance and Repair Activity on Submersible Pump 

A submersible pump (also known as a sub pump or an electric submersible pump (ESP)) is a device with a hermetically sealed motor that is close-coupled to the pump body. The entire assembly is immersed in the fluid that will be pumped. The primary benefit of this type of pump is that it prevents pump cavitation, which is caused by a large elevation difference between the pump and the fluid surface. 

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Unlike jet pumps, which generate a vacuum and rely on atmospheric pressure, submersible pumps push fluid to the surface. Submersibles, which are utilised in heavy oil applications with hot water as the motive fluid, employ pressured fluid from the surface to drive a hydraulic engine downhole rather than an electronic motor.

Working Principle of Submersible Pump

Electric submersible pumps are multistage centrifugal pumps that operate vertically. Liquids driven by the impeller lose kinetic energy in the diffuser, where it is converted to pressure energy. Radial and mixed flow pumps use this as their primary operating mechanism. The motor in the HSP is a hydraulic motor rather than an electrical motor, and it can be closed cycle (keeping the power fluid separate from the generated fluid) or open cycle (keeping the power fluid separate from the produced fluid) (mingling the power fluid with the produced fluid downhole, with surface separation).

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A mechanical coupling at the pump's base connects the pump shaft to the gas separator or protector. Fluids are drawn into the pump via an intake screen and elevated by the pump stages. Other components include radial bearings (bushings) that run the length of the shaft and provide radial support to the pump shaft. An optional thrust bearing absorbs some of the axial forces generated by the pump, but the protector's thrust bearing absorbs the majority of those forces.

There are also screw-type submersible pumps, which utilise a steel screw as a working element. The screw enables the pump to operate in water containing a high concentration of sand and other mechanical contaminants.

Contents in Maintenance and Repair Activity on Submersible Pump

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Why Perform Preventative Maintenance?

• Identification of Major Components
• Cost of Pumping
• Pump and System Curves
• Best Efficiency, POR, AOR

What Does Preventative Maintenance Consist Of?

• Electrical
• Mechanical
• Checklist
• Maintenance Report

What If My Pumps Need Repair?

• Difference between a repair and a complete overhaul
• Procedure for refurbishing a submersible pump

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