Motor Lead Extension

The Motor Lead Extension is a “special power cable extending from the pothead on the motor to above the end of the pump where it connects with the power cable (API RP 11S4).

A low-profile cable (flat configuration) is usually needed in this area due to limited clearance between the pump housing and the well casing”.

It is recommended to select a length at least 6 ft. (1.8 m) longer than the upper end of the pump. The length of MLE has to be select in a way to avoid a splice over a tubing collar. Doing so could allow the cable to catch on the wellbore casing and damage the equipment.

The motor lead extension operates under extremely adverse conditions. This is due to the restricted size, the high mechanical stresses, and the high temperatures involved. Because of these effects, motor lead extensions are usually replaced every time a cable is reused.

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Submersible Pump System Overview

The submersible pump system consists of both downhole and surface components. The main surface components are transformers, motor controllers, junction box and wellhead. The main downhole components are the motor, seal, pump and cable. Additional downhole components may be included to the system: data acquisition instrumentation, motor lead extension, cable bands and protectors, gas separator, check and drain valves.

The following video gives a quick equipment overview of the ESP submersible pumping system:

 

The following figure shows schematic diagram of a submersible pump installation:

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Step 8 – Downhole and Surface Accessory Equipment

This article “Downhole and Surface Accessory Equipment” is the step 8 of the nine-step procedure to design an ESP with an efficient and cost-effective performance. The required downhole and surface accessory equipment are discussed and recommended practices are highlighted.

Downhole Accessory Equipment:

  • Motor Lead Extension (MLE):

API RP 11S4 defines the Motor Lead Extension as a “special power cable extending from the pothead on the motor to above the end of the pump where it connects with the power cable. A low-profile cable (flat configuration) is usually needed in this area due to limited clearance between the pump housing and the well casing”. It is recommended to select a length at least 6 ft. (1.8 m) longer than the upper end of the pump. The length of MLE has to be select in a way to avoid a splice over a tubing collar. Doing so could allow the cable to catch on the wellbore casing and damage the equipment.

  • Banding Cable Protectors:

Cable protectors are used to protect the Motor Lead Cables from damage during installation, operation and pulling. The figures below show an example of cable protectors.

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