Study on Optimization of Structural Parameters of Downhole De-oiling Equipment of Hydrocyclones in the Single-Well Injection-Production System

It is difficult to guarantee the downhole oil-water separation performance of a hydrocyclone in single-well injection-production technology system with ultra-high liquid inlet flow rate. An innovative downhole de-oiling equipment of hydrocyclones (EHC) is proposed to encounter the technical bottleneck of down hole oil water separation caused by ultra-high inlet flow rate. The computational fluid dynamic method and the response surface method (RSM) are used to analysis the characteristics of EHC flow field and improve its performance. Herein, the optimization analysis of significant structural parameters is conducted via RSM. The optimal structural parameters of EHC are obtained to enhance the separation performance. The results show that when the inlet length L2 = 41.25 mm, inlet diameter ϕ1 = 22.5 mm, the overflow diameter ϕ4 = 4.5 mm, and the center tube diameter ϕ3 = 30 mm the separation efficiency of EHC can reach the maximum value 94.98%. The separation efficiency of optimal EHC is 6.18% higher than the original one. The indoor experiments of separation performance are carried out to verify the reliability of numerical simulation results. The simulation results is in good agreement with experimental ones, the feasibility of optimal EHC and the reliability of simulation method are verified.