Experimental Study on the Performance of Electrical Submersible Pump Operating with Ultraviscous Oil

The production of high--viscosity crude oil can be challenging owing to portfolio limitations and lack of energy efficiency in artificial lift systems, especially for ultraheavy oil in deepwater fields. In recent decades, the electrical submersible pump (ESP) has improved significantly, and this technology is commonly applied in this context. However, few studies in the literature discuss the behavior of these pumps with nonconventional oils such as ultraviscous ones. This work investigates the performance of a 10--stage ESP, when it operates with a single--phase flow of ultraviscous oil. For this purpose, an experimental circuit was set up; the pump was submitted to tests in which the viscosity of the fluid varied from 8 to 4,170 cp and rotational speed between 1,200 and 3,500 rev/min. A subsequent analysis compared the pump's experimental viscous performance and the theoretical performance calculated by the methods available in the literature. This analysis highlighted the lack of precision of the existing correction performance models, and new empirical correlations are proposed to correct the ESP performance with viscous fluid. There were doubts at first as to the possibility of ultraviscous block, but the ESP model tested handled fluid with a viscosity up to 4,170 cp. Finally, the performance parameters of the ESP were calculated using a phenomenological 1D model based on the loss analysis developed by the authors, which revealed good results and a powerful tool to adjust the size of the ESP for definitive production system.