Simple model of electric submersible pump in gassy well

Electric submersible pump (ESP) is a widely used artificial lift method for oil production. Free gas at the pump intake can degrade the ESP performance. Degradation can be in the form of reduced head, surging and gas locking.This paper presents a new easy-to-use model intended for the field engineer. The model's parameters are obtained by using linear multiple regression analysis on measured data. The model is not pump-specific as it uses dimensionless head and rate. In addition, a critical model and a simple equation are presented to predict the start of surging, which can cause pump instability and even gas lock. The study also gives the field engineer an idea of how the liquid-only affinity laws are impacted in multiphase flow conditions.Compared with available models, the presented pump head degradation model and the critical model are both the best.