Abstract
Maintaining oil production while both water cut and reservoir pressure are changing with time is a challenging task especially for fields equipped with artificial lift systems such as Electrical Submersible Pump (ESP). ESPs have a defined recommended operating range (ROR) that can reduce the flexibility of the system therefore a variable speed drive (VSD) unit is being used to extend the ROR. A surface choke is also another option to adjust the flow rates and control the ESP to operate within its recommended range. However, inefficient use of both options can be detrimental on the life cycle of the production system.
High VSD Frequency will increase the motor speed which leads to increased power consumption. Low choke setting causes high hydraulic losses across the choke that can lead to wastes of energy. In oil fields equipped with ESPs, power consumption as well as ESP run life play a significant role in specifying the operation cost and economical life of the field. Therefore, it's essential to optimize the operation conditions of the ESP to optimize the operation conditions of the ESP through minimizing power consumption while maintaining a production rate that fall within the pumps ROR. Utilizing a technique that can quickly provide the best choke and frequency setting is a key to achieving more optimized operation in a dynamic field.
This paper will discuss an in-house developed application that can calculate the minimum ESP motor operating frequency and the optimum choke setting point required to maintain the production rate at the minimum power consumption and lower motor speed. With the availability of real-time data from the surface and down-hole equipment, the optimization process was automated by collecting data and modeling surface equipment and ESP. this application is being used to optimize an entire field and the pilot test showed very promising results. A substantial 2000 KVA, which is equivalent to 1600 KWh, was saved by adjusting only 57 wells.