Impact of the Geometrical Configuration of Electrical Submersible Pump Impellers on Run Life and Sand Stuffing: A Case Study and Recommended Practice

Abstract

The objective of this study was to identify the root cause of the premature frequent failures of electrical submersible pumps, in a particular oil field, aiming to extend their run lives so oil deferment, liquid lifting costs, and unit production cost are reduced. Dismantle, inspection, and failure analysis (DIFA) approach was used to visually inspect the pumps to identify the cause of failure. The inspection inferred that the failures were mainly due to sand accumulation (stuffing) in the impellers of radial flow pumps, while it was not observed in the mixed flow impellers that have shown good performance at the same well conditions. This finding was then experimented on many wells and proved to be correct as demonstrated in this paper.  Eventually, the result of this research was technically proved as being attributed to the geometrical shape of the impeller flow path, the study has correlated sand stuffing failure with flow path geometry of the impellers. The study projected these results to an established specific speed model (N_s) and recommends a pump sizing approach for mild sand-producing oil wells to cater for the geometrical flow configuration of the pump impellers.