Abstract
A four stage helicoaxial pump was tested under varying operating conditions. A range of inlet pressures, rotational speeds (3000, 3600 rpm), and gas void fractures (GVFs) were considered for two fluid viscosities. The head developed and power input to run the pump were recorded. Head, power input and efficiency decrease as the GVF increases with best efficiency point (BEP) moving towards lower flow rate conditions. Dimensional analysis was conducted to evaluate the applicability of current affinity laws to the two-phase flow performance of the pump under consideration. Dimensionless head coefficient and power coefficients were defined for two-phase flow, considering the homogeneity in the two-phase fluid properties. Deviations in the two-phase affinity coefficients from the common law curve increases with GVF. To bridge this gap, a new correlation is proposed with a revised flow coefficient that allows all the head coefficient data to collapse on a single line with a greater degree of accuracy.
Highlights
Electrical submersible pumps (ESP) are a commonly used artificial lift system for upstream oil and gas production when the reservoir pressure is insufficient to meet the desired production rate.Reservoir production is quite often characterized by the presence of gas in liquid flow
Pump-head and power input systematically degraded with an increase in gas void fractures (GVFs)
Pump-head and power input systematically degraded with an increase in GVF at at the pump inlet
Summary
Reservoir production is quite often characterized by the presence of gas in liquid flow. Standard designs of mixed-flow pumps have limited gas-handling capabilities. Evaluating gas presence in the working fluid is of significant research interest due to its effect on pump performance and reliability. The prediction of the multiphase flow condition of well fluid can help facilitate better well control and operation. Various researchers focused on understanding the performance of standard mixed-flow pumps under two-phase flow conditions, especially gas and liquid. Cirilo [2] conducted two-phase flow testing of three different pumps for varying inlet pressures, speed, and number of pump stages using water and air as test fluids. The pump performance was characterized using inlet pressure, speed and number of stages. Romero [3] tested a 12-stage ESP with a specially designed impeller for two-phase flow
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