Modeling of Transient Two-Phase Flow in a Well After Startup of Electrical Submersible Pump

A numerical model of transient two-phase in a wellbore after startup of electrical submersible pump (ESP) was developed in the present study. The model consists of three modules. The first module, the wellbore model, predicts two-phase gas-liquid flow in the wellbore. The second module describes performance characteristics of centrifugal pumps. The third module, the reservoir model, predicts the variable well inflow after startup of the pump. The wellbore model is based on a drift-flux model (three equation model) of two-phase flow. The relative velocity is determined using a flow regime-dependent slip correlation or a mechanistic steady flow model. Field data collected during a startup of an ESP well were analyzed. This analysis showed that the response of the system to the ESP startup is governed by dynamic interacticn between the well and reservoir. The results obtained can be used for the development of production startup or restart procedures for wells equipped with ESP systems.