Abstract
A reduced outer diameter (OD) high flow rate pump, a high power permanent magnet motor (PMM) and the most usual Variable Speed Drive (VSD) available in the field were selected. The VSD with minimum capabilities to run the PMM with a "scalar V/Hz" control algorithm were validated. The validation tests were performed in a testing loop where the best parameter configuration was selected to match a proved "vector control" Drive performance from the same motor vendor. Key parameters such as magnetizing current at minimum level were identified.
The system was installed in Tello field, Colombia. It was started and operated without any issues following strict safety procedures and barriers.
This PMM application has delivered energy savings above 15% versus the previous induction motor (IM) application. The energy consumption decreased from 625kWh to 478kWh, 147kWh less, representing a saving of USD 85,000 per year.
The scalar (volts/Hz) control has shown good motor control for the application conditions: high water cut (96%), casing 7" 26#, 8000 ft, deviated well, and rates above 9000 BFPD.
Reliability improvement is established by replacing 990HP induction triple tandem motor (102ft) for a single 980HP Permanent Magnet Motor (34ft). The PMM showed a lower operating temperature and eliminated current peaks during motor start-up. The diameter of the pump was reduced by 0.9" (from 5.38" series pump to 4.49" series pump), providing a faster installation, reducing the risk of MLE damage or ESP equipment stuck due to reduced clearance. The run life of the well increased from less than 6 months to more than 3 years. As expected, this new downhole configuration presented an improvement in reliability compared to conventional ESP equipment.
A second well was installed confirming the benefits of the approach, and the Field Operator Management has approved the PMM massification in the Tello field.
This application proved the option of running and benefiting from reduced OD high flow rate pump and the Permanent Magnet Motor technology utilizing existing surface equipment, facilitating the financial decision, and improving reliability.
