High Rate Slim ESP Viability Assessment in the Field

Abstract Producing oil at full potential with an electrical submersible pump (ESP) in a slim well remains a challenge in the petroleum industry. A conventional slim ESP system is limited in produced oil delivery rate with an associated risk of damaging the motor lead extension (MLE) of the ESP during the running in hole due to tight clearance. Finding a high rate new slim ESP technology is crucial to enable production of wells at full potential and eliminate slot recovery. This paper shares the success stories of testing two high rate slim ESP installations, and provides the advantages and disadvantages for each of the two approaches for high rate slim ESP design. The high rate slim ESP design options were assessed through field trials collaborating with different manufacturers. The slim ESP viability evaluation metrics were maximum rates, ESP performances, completion installation simplicity and surface controller compatibility. These metrics ensure eliminating unnecessary costs of ESP replacement in the field. The first design option is an inverted ESP design with an induction motor installed at the top. Such a design is advantageous in allowing a pump with a bigger outer diameter (OD), eliminating MLE installation on the pump housing due to an increased clearance, and consequently achieving a higher rate. The second design option uses a permanent magnetic motor (PMM) in a standard ESP configuration. The second design with the smaller ESP OD allows high motor speed, thus providing a higher head capacity and higher flow rate. A modification in the variable speed drive (VSD) design is required to enable controlling the PMM. The field trial result revealed multiple benefits of the high rate slim ESP systems in the field. The high-speed system that utilizes PMM retains the standard ESP configuration, which simplifies well completion and avoids installation complexity. The reduced ESP OD provides more clearance in the well, leading to minimized possible MLE damage during running in hole. Although the VSD modification is possible, the PMM maximum speed will be limited by the maximum capacity of the existing transformer installed in the platform. Finally, both systems lead to a significant cost avoidance by eliminating the need for slot recovery of the produced well at full potential in a slim-well, and avoiding unnecessary replacement of ESP surface equipment. The two systems were already successfully evaluated with a continuous run for more than 365 days without any issues.