Study On Structural Optimization And Separation Performance Of Pumping Gas-liquid Separator

In some peripheral blocks of Daqing,due to the use of CO2 injection flooding methods for extracting oil, the gas-liquid ratio of well is relatively high, and the high levels of gas-liquid ratio on oil production has become increasingly apparent.Thus, gas has gradually become the main reason of affecting pump efficiency. After many years of experimental research, the effective measure is to install the gas-liquid separator at the inlet of the pump,using the downhole gas-liquid separator to separate the fluid from the gas before entering the pump, reducing the content of the gas in the pump fluid. Although the gas-liquid separator has been widely used in oil field, the gas-liquid separation effect is not ideal when the gas content is relatively large. Therefore, further research on gas-separation efficiency of downhole gas-liquid separator has important significance in improving the pumping efficiency and optimizing the structure of gas-liquid separator.Based on the theory of gas-liquid two phase flow, an exploratory study on the gas-separation efficiency of downhole gas-liquid separator is made in this paper. According to the theoretical calculation formula of gas-liquid separator, 3-D flow model of gas-liquid two phase is established. By using the computational fluid dynamics software FLUENT and the Eulerian model,carry out the numerical simulation of gas-liquid separator of gas-separation efficiency, and optimize the structure and size. By changing the parameters: tube outer diameter, the inner tube diameter, separate length of the gravity gas-liquid separator, conduct multiple-group simulation and analyze the results. Analysis showed that: when the internal diameter of the outer pipe is larger, the center pipe outside diameter is smaller, and the separation chamber length is relatively small, the separation effect of gas-liquid separation device is better. After the improvement of the inner and outer tube connecting port size of the superior separator of the bipolar gas-liquid separator is 10 mm, the separation effect can be achieved. In northeast petroleum university engineering training center, design and set up an experimental device to simulate downhole gas-liquid separation. Through the indoor experiment methods, conditions of use and separation effects of Gas-liquid separator was studied. Research shows that: when the pump stroke for 1-5 and gas-liquid ratio is 2000m3/t,efficiency of unipolar gas-liquid separator pump maintained in above 90%, when the pump stroke for 7-9 and gas-liquid ratio is 1000m3/t,pump efficiency is above 70%.The research results of this paper can provide theoretical basis for the analysis of the separation efficiency of gas-liquid separator and the optimization of structure size ofgas-liquid separator, lay theoretical basis for improving the pump efficiency.