Optimization and experimental validation of a high-efficiency oil–water cyclone separator for well testing conditions

Abstract The performance of surface oil–water cyclone separators impacts the measurement accuracy of crude oil produced from exploration and appraisal wells, thereby influencing the formulation of exploration and development plans. To obtain the optimal structural configuration for cyclone oil–water separators, this study optimizes the design of a high-efficiency oil–water cyclone separator suitable for special conditions in well testing. A numerical simulation was performed using the discrete phase model to analyze the three-dimensional turbulent swirl field of the oil–water phases within the separator. Separation efficiency and pressure drop were used as evaluation criteria. The Plackett–Burman experimental method was employed to evaluate six factors affecting separation performance, with oil outlet diameter and cyclone chamber cone angle identified as significant factors. Mathematical models for separation efficiency and pressure drop were developed based on these factors. The central composite design method was then applied to investigate the interactive effects of oil outlet diameter and cyclone chamber cone angle on separation efficiency and pressure drop. The optimal parameter combination was determined: oil outlet diameter of 4.241 mm and cyclone chamber cone angle of 9.622°. The predicted separation efficiency was 93.870%, and the predicted pressure drop was 48.287 kPa. Field tests of the optimized cyclone separator verified the rationality of these optimized parameters, achieving a separation efficiency of 92.9%. This research offers a foundation for optimizing the design of oil–water cyclone separators.