Investigation of the ejector characteristics to improve the technology of pumping gas from the annular space during well operation by electrical submersible pump unit

The article presents the results of experimental study of the influence of operating fluid pressure on the ejector characteristics for subsequent use in perfecting the technique of selecting the most suitable flow part of a jet apparatus during well operation with electrical submersible pump unit (ESP) units and pumping gas from the annulus to the tubing. The characteristics of the jet apparatus were studied on an experimental stand, on the basis of which pressure distribution curves were constructed along the length of the flowing part (mixing chamber and diffuser) of a liquid-gas ejector at various pressures of the working fluid in front of the nozzle. The dependences of the relative dimensionless pressure drop and the efficiency of the ejector on the pressure of the working fluid in front of the nozzle to assess the efficiency of the ejector at various operating pressures were also represented. The dependence of the optimal operating mode of a liquid-gas ejector on the magnitude of the working pressure is revealed. In the experiments, the pressure distribution curves along the length of the ejector were measured and the characteristics of the jet apparatus were obtained when gas was evacuated by a liquid jet with accuracy suitable for practical purposes. It is shown that with a decrease in the working pressure, the character of the pressure distribution along the length of the ejector dramatically changes. The provision is added that the most optimal mode for a liquid-gas ejector is the mode in which the process of mixing flows is completed directly in front of the diffuser-the optimal mode also depends on the magnitude of the working pressure. The results of experimental studies expand the possibilities of optimizing the flow part of ejectors for use in various pump and ejector technologies for SWAG in order to utilize associated petroleum gas and increase oil recovery. Based on the results of experimental studies presented in the article, the most suitable for the characteristics of the flow part of the ejector can be selected, including the length of its mixing chamber during operation with ESP units and pumping gas from the annulus into the tubing. © 2020, Neftyanoe Khozyaistvo. All rights reserved.