Improving the operation of pump-ejector systems at varying flow rates of associated petroleum gas

Application of pump-ejector systems for the utilization of associated petroleum gas reduces the negative environmental impact of its flaring, and also allows the implementation of a promising method of water-gas stimulation of the formation, which effectively increases oil recovery. Equally feasible is the use of pump-ejector systems in the operation of oil wells with a high gas factor, low bottomhole pressures to increase production rates and increase the turnaround period. A significant change in the flow rate of associated petroleum gas over time is a serious problem for the efficient operation of pump-ejector systems for the utilization of associated petroleum gas. To ensure the rational operation of the pump-ejector system under the condition of a variable flow rate of associated petroleum gas, experimental studies of a liquid-gas ejector characteristics were carried out. The article presents the results of the research, obtained pressure-energy characteristics of the investigated jet apparatus at various values of the working stream pressure before the ejector nozzle. The possibility of adapting the operation of pump-ejector systems to changes in the flow rate of the pumped gas, regulated by the working pressure and fluid flow rate through the nozzle is revealed. To successfully change the operation of the pump-ejector system, the possibility of frequency regulation of the pump shaft's rotation at changing gas flow rates in a small range of values is considered. With a large difference in the values of the possible flow rate of associated petroleum gas, it is recommended that frequency regulation should be supplemented by periodic short-term operation. The possibility of increasing the efficiency of the pump-ejector system when using salt solutions with a concentration that contributes to the suppression of bubble coalescence is noted. © 2019, Saint-Petersburg Mining University. All rights reserved.