Electric Submersible Pump Performance and Numerical Modeling in Two- Phase Flow

Abstract

Abstract Differential pressure (DP) between stages of multi-stage diffuser type centrifugal pump of an electric submersible pump (ESP), system was measured in a two-phase flow environment. The test results were used to improve existing numerical models and bubble size models for better prediction and to improve the design process. This paper details the comprehensive testing and model validation process for ESP pump stages. Various sizes and types of ESP pump stages were tested in a high-pressure two-phase flow loop. Each stage performance was monitored using high-precision DP transducers. Test results were used to calibrate numerical simulation in two-phase flow. The correct bubble size for individual test conditions was calculated based on the test results. The bubble size calculation was crucial for good model prediction in two-phase flow. After several types and sizes of ESP stages were validated, same bubble size model could be used on other pump stages that have similar sizes and designs. Presented in this paper are the actual gas volume fraction (GVF) handling capabilities of typical ESP stages, including the effects of flowrate, GVF, pump speed, inlet pressure, flow mixing and inlet/outlet effects. After the lab test was complete, computational fluid dynamics (CFD) was used to investigate the hydraulic performance of the same stages and conditions tested in the lab. Simulation results were compared with test results and optimized for the correct bubble size of the secondary phase. The current bubble size model predicted very well for the lower GVF combined with large flow rate pump. The low flow pump had DP errors in excess of 10% for GVF values over 40%. The validated numerical model can be used to improve pump modeling and enable improvements in pump design that could increase the gas-handling capabilities of pump stages of similar size and styles.