Defining a New Era for Induction Motors | SLB

Defining a New Era for Induction Motors

Published: 09/27/2021

Schlumberger Oilfield Services

Induction motors have been widely used in the ESP industry for decades. Motor operation, control, and optimization are well-understood topics among providers and final consumers, who strive to get the most efficient electrical machine in the well to reduce power consumption and, consequently, operating expenses.

This paper presents a case study for a newly redesigned induction motor and changes made in its design and construction. A field trial of two wells deployed with the new motor and a comparison with a well deployed with the standard motor are described. Field and simulated data are used to analyze the electrical performance and power consumption. The test results included are from wells in the US Rocky Mountains. Additionally, some of the motors in this test were manufactured with a high-performance thermally conductive and electrically insulative windings encapsulation, which is further discussed in the paper.

The increased efficiency was achieved through an optimized electromagnetic design that helped to reduce the motor total losses. Efficiency gains were measured against standard motor design through laboratory testing, and the result showed 2.2 to 2.5% higher efficiency for the newly developed motor. With the higher power density, the motor length was shortened from 20 to 25% during the field trials, reducing the total length of the string. In addition to the optimization of motor length, the newly redesigned motor generates a lower core temperature when compared to a previous motor of the same length and subjected to the same load. This fact allows the motor to be loaded up to 25% above its nameplate rating, improving the horsepower rating and opening a new era for highly flexible induction motors.

The gathered results showed that the newly redesigned motor provides higher efficiency and lower total electrical power consumption compared to the standard induction motor that would have been used in those applications. Both results were evidenced in controlled laboratory testing and field trials. A further comparison of similar ESP equipment configuration running with former motor versions is also provided, as well as design comparison cases between the expected results of the previous and the newly designed motor.

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