Electrical Submersible Pump is playing a pivotal role in crude extraction. It is one of the innovative technologies at this stage being used globally to produce wells with a higher flow rate. Today, ESP systems are acting as an effective medium for companies to operate efficiently with higher production. As of today, ESPs are being used at many different applications like dewatering, multi-zone production etc, however, technology use shall need minor modification to operate ESP with longer run life. In the coming era, fields are expected to enter the EOR (Enhanced Oil Recovery) stage, wherein every drop of the reservoir would add importance in production for companies. ESP with PMM motors is the typical application in such EOR, adding many benefits over the operation of IM application. Polymer flooding is used in some wells in the onshore Rajasthan field to perform enhanced oil recovery (EOR). The typical static bottom hole temperature of wells in this field is 65°C. When using ESPs with industry-standard induction motors, the motor operating temperature has been recorded at 105°C on initial startup. Polymer deposition on the motor causes heat to rise, with operating temperatures escalating quickly to 180°C. Temperature-induced polymer deposition requires frequent back-flush interventions to maintain target production and results in premature motor failure. Because PMMs have been shown to operate at lower temperatures than induction motors, they were tested in ESPs in this field in an attempt to increase motor run life and reduce ESP failure rates. Four wells were targeted for this study with the goal of limiting motor temperatures to 80°C without impairing production. Detailed ESP designs are explained along with the results. Unique ESP designs were made for four wells that use PMMs rated for 3600 RPM @ 60Hz. The operating plan called for limiting the motor load to no more than 60% to keep motor temperatures around 78°C. PMMs operate at 15-20% lower temperatures due to reduced frictional, mechanical, and hydraulic loss with higher efficiency up to 95%. PMMs were installed with high-efficiency pumps capable of producing 5000-10000 BFPD. Target production rates were maintained in all four wells, with motor temperatures remaining around 78°C during operation. The result was the longer motor and ESP run life compared to offset wells in the field using ESPs with induction motors. The PMM systems also reduced the need for back-flushing operations, reducing CAPEX and lowering intervention costs. PMMs were shown to maintain low motor temperatures, reduce polymer deposition, and significantly increase economic well life.
This paper examines the outcomes discovered when using PMMs in a difficult EOR well environment where only asynchronous induction motors had been previously used. It shows that PMMs can be used to control motor temperatures, reduce polymer deposition, and increase run life in the conditions presented by this polymer flood application.