Optimization of sand-carrying lifting performance in a negative pressure jet sand-washing device based on the novel iterative Taguchi method and CFD

With prolonged oil well production and rising water content, sand production has become a significant challenge in China’s Ludong area (Shengli Oilfield). Without timely sand removal, sand accumulation can cause severe issues like formation sand influx. To reduce sand deposition and enhance efficiency, a negative pressure jet sand-washing device was designed using the Venturi jet principle and confined space jet theory, combining jet sand-washing and sand-carrying lifting. Since the device’s performance is heavily influenced by its structural dimensions, the team used Computational Fluid Dynamics (CFD) and the control variable method to analyze key factors. Results showed that throat diameter, length, diffusion angle, throat-to-nozzle distance, and jet nozzle outlet cylindrical length significantly impact performance. To further enhance the device’s performance, the team developed a novel iterative Taguchi method, combining it with CFD to optimize key structural dimensions. Results showed the factors affecting sand-carrying and lifting performance, ranked by importance: throat diameter, diffusion angle, throat-to-nozzle distance, jet nozzle outlet cylindrical length, and throat length. The device optimized with the novel method achieved 31.3% efficiency, surpassing the unoptimized (24.2%) and traditionally optimized (29.8%) versions. This proves the superiority of the novel iterative Taguchi method. The research offers a new structure for downhole sand-removal devices and a new method for mechanical device optimization.