Extending system run life impacts well profitability by cutting artificial lift replacement costs and reducing production losses from downtime. The run life of Electrical submersible pumping (ESP) motor can be increased by reducing the operating temperature of the motor. On the other hand, cooler-running motors can be used for high-temperature wells, where downhole temperatures may be a limiting factor.

Controlling motor temperature is important for increasing ESP run life as motor temperature plays a key role in motor failures. Power losses in ESP motors were analyzed for various operating conditions. Power losses are the source of heat generation and the resulting temperature rise in the ESP motor. The internal motor temperature depends upon heat generation in the motor, well parameters, operating conditions, as well as the design and materials used to manufacture the motor.

To reduce internal operating temperature, the motor should efficiently transfer the heat generated within the motor to the well fluid. New techniques for efficient heat transfer were developed and ESP motors with an enhanced motor-cooling design were built. These modified motors were tested in wells under controlled conditions in Claremore, Oklahoma and in two field trials in conventional and SAGD wells. The results showed a significant decrease in the internal operating temperature. This paper will address various contributing factors affecting motor internal temperature, an enhanced cooling design, and field trial test results.

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