The use of multistage parallel micro cyclones to achieve downhole oil-water separation can increase the oil volume fraction of the produced liquid,and also meet the requirements of high treatment capacity.When working in the well,if the structure of the flow field in tubing-casing annulus formed between the oil-water separa-tion equipment and the casing is unreasonable,the flow rate obtained by each stage of the micro cyclone group is uneven,which affects the overall separation performance of the multistage parallel micro cyclone separation device.In this paper,based on numerical simulation and response surface Box-Behnken experimental design method,a mathematical model was constructed for the structural parameters,flow nonuniformity coefficient and maximum pressure loss of the fluid domain in tubing-casing annulus formed by the separation device and casing,and the ef-fectiveness of the model was verified.The results show that when the inlet spacing and angle of each stage of micro cyclone are 400 mm and 90° respectively,the total number of stages is 3 and the ratio of inlet and outlet area is 0.5,and the optimized flow nonuniformity coefficient decreases from 0.026 53 to 0.012 89,with a decrease of 51.41%.Compared with the initial structure,when the Reynolds number varies between 3 000 and 8 000,the flow nonuniformity coefficient of the optimized structure is relatively stable under various working conditions,with a maximum reduction of 0.047 08 and a minimum of 0.011 25.The optimized structure exhibits good uniform flux performance and adaptability.The analysis results provide reference for the design and application of downhole mul-tistage parallel micro cyclones.
维普
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