During 2012, BakerHughes, ConocoPhillips and Nexen Inc. continued their research partnership [Waldner 2011] with a new experimental test program focused on the thermal performance of Electric Submersible Pump (ESP) systems for Steam Assisted Gravity Drainage (SAGD) applications, which was completed in the high-temperature flow loop at C-FER Technologies. Accurately monitoring the internal temperature of the ESP motor is a key consideration when trying to increase the operational longevity of an ESP system for any application; however, as the SAGD process develops, understanding this temperature profile has become more critical. This test program included several tests at various fluid temperatures and ESP operating conditions that helped determine the thermal performance of the ESP motor. Another unique aspect of this test program was the incorporation of two different temperature monitoring methods at approximately the same position on the internal and external base of the ESP motor: one internal probe positioned near the motor windings via a fiber optic sensor and one external skin temperature RTD positioned on the motor surface to monitor this important temperature differential. This paper presents the equipment and instrumentation used, and demonstrates some of the more interesting test results, thus providing further insight into the thermal performance of this ESP motor under representative SAGD conditions between 220°C (428°F) and 250°C (482°F).

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.

A Permanent Magnet Motor (PMM) designed to break the 300°C barrier was previously presented that included many advancements to greatly improve the operating temperature and reliability beyond the ability of current equipment [1]. A key design element is the inclusion of a squirrel cage in the PMM rotor that results in a hybrid construction. This paper will delve into the rationale for the hybrid configuration and will assess motor performance using electromagnetic simulations and validation testing. PMMs are used in many industrial applications and have recently started to gain traction in oil and gas upstream production applications. A significant issue is the PMM compatibility with existing motor drive equipment and their need for special provisions to operate at the end of long cables without position sensors. A hybrid configuration help overcome these limitations and allows operation with conventional variable speed drives using a standard scalar controller as used with induction motors. The design, development, and qualification of the hybrid PM rotor construction were undertaken using a rigorous analytical approach combined with extensive validation testing. The motor is designed to maintain stability under the severe transient conditions in the SAGD environment, where the produced emulsion rich in gas and solids creates highly variable conditions for the motor and controller. A detailed electromagnetic model of the motor for configurations with or without the squirrel cage was undertaken to demonstrate the effectiveness of the hybrid configuration to maintain speed control stability. A time stepped method was used to simulate the motor start with simulated loading conditions, reflecting the starting and operating conditions with breakaway torques up to full load torque condition and 50% transient loads. The squirrel cage was successfully integrated within the rotor structure of a 150hp PM motor. Extensive design and thermal-structural analysis ensured the construction was acceptable for operation in the ranges −40°C to 350°C. Validation testing was then performed to demonstrate the hybrid PM motor construction functioned for use with conventional and legacy variable frequency drives.

The development of a High-Temperature Permanent Magnet Motor (PMM) was initiated with the main objective to bring forth a technical solution to significantly increase temperature capability and run life of ESPs in Steam Assisted Gravity Drainage (SAGD) beyond current technology. This is in response to operators needs for improved safety margins and increased production rates. Existing ESP motor technologies are limited to approximately 300°C internal motor winding temperatures, driven by the available motor electrical insulation systems. The use of PMMs in SAGD was also prohibited by the availability of magnet materials capable of operating in such temperatures, without partial or full de-magnetization. The project's aim is to break this barrier and extend internal temperatures to 350°C and beyond, allowing well ambient temperatures to be pushed beyond the 260°C downhole environment. In addition, for assurance of motor reliability, rigorous and methodical design validation and qualification testing of basic materials, components, sub-assemblies were undertaken.

One of the main functions of an ESP Seal Chamber Section (also known as a "Protector") is to provide a rotating mechanical seal to protect the motor oil from contamination. These seals are susceptible to damage due to a high concentration of fines in production fluids scoring the sealing surfaces. A novel device to be used in conjunction with the Protector has been developed and tested. The device, called the Guardian, draws in wellbore fluid, through a two-stage dynamic separator, to continuously flush the seal with filtered fluid. The device, located between the pump intake and the Protector, accelerates the solids and ejects them back into the fluid stream. Only filtered fluid remains after the last stage. This filtered fluid is circulated through the device's journal bearings to replenish the fluid in contact with the mechanical seal. This filtered fluid protects the seal and manages its heat rejection. The device solves one of the enduring challenges to run-life of ESP Protectors prevalent in applications such as tight oil and SAGD. The technology is a step change to existing solutions and provides service companies and operators a solution applicable when solids and fines pose a risk to the mechanical seal, a critical part of an ESP and its run life.