Objective In order to improve the separation rate of oil-water-sand mixed liquid in the process of oil exploitation and transportation, an integrated oil-water-sand pre-separation equipment was designed and its practical capability was tested.

Methods Based on the orthogonal test, the structural parameters of the cyclone oil-water separation unit were optimized by numerical simulation method, and the optimum operating conditions were explored. The accuracy of simulation results and the feasibility of designed equipment size were verified by an example.

Results Structural parameters of the oil-water-sand pre-separation equipment were determined as follows: the main diameter of the cyclone of 66.5 mm, the overflow port diameter of 4.6 mm, the bottom flow port diameter of 14 mm, and the large cone angle of 20°. The optimal operating conditions under this size were identified with the oil phase volume fraction of the mixed liquid was set at 10%. The simulation demonstrated that the optima inlet flow rate, the overflow split ratio, and the oil removal efficiency was 15 m/s, 15%, and 83.1%, respectively, while the corresponding values were 15 m/s, 15%-20%, and 79% in real tests.

Conclusions The results of numerical simulation were consistent with the experimental results. The optimized equipment can satisfy the requirements of oil-water separation pretreatment and has great application prospects.