Research on Adaptability of Downhole Two-Stage Series Hydrocyclone Separation Technology

In view of the disadvantages of the separation technology in the same well injection -production technology, the downhole two-stage series hydrocyclone separation technology is put forward in order to overcome the shortcomings of the existing downhole oil-water separation technology which is not suitable for the well conditions. Using computational fluid dynamics (CFD) software to simulate the movement process of the fluid, analyze the movement state of oil-water two-phase liquid in the separation process, and focus on exploring the influence of the split ratio, treatment capacity and water content change on the technical performance of the downhole two-stage series cyclone separation. When the water content reaches 97% and the total split ratio reaches 36%, the separation performance increases with the increase of the flow. Through laboratory test and research, the best operation parameters are determined as total diversion ratio of 30%–35%, treatment capacity of 4.8 m3/h–5.1 m3/h, the best separation efficiency of downhole two-stage series hydrocyclone separation technology is over 92%, and the pressure loss is less than 0.4 MPa. Through the numerical simulation analysis and laboratory test, the feasibility of the downhole two-stage series hydrocyclone separation technology is proved in theory and practice, which lays a solid foundation for the further improvement and promotion of the technology.