Investigation into the Migration Pattern of the Knot-shaped Diverters in Vertical Wells Based on Large-Scale Field Visualization Experiments

Temporary plugging and diversion technology serves as a critical enhancement for vertical well stimulation through production optimization and zonal isolation. Addressing the challenge of evaluating plugging effectiveness under realistic well conditions, this study employs large-scale visualized experiments with full-scale wellbore configurations to investigate the migration and plugging behavior of knot-shaped diverters (KSDs). A real-time monitoring system was implemented to track diverter movement and plugging formation under varying flow rates and pressure conditions. Four knot size ranges (10-12 mm, 13-15 mm, 16-18 mm, and 20-22 mm) were tested in simulated wellbores containing 3-6 perforation clusters. Results demonstrate that larger knot sizes (16-18 mm and 20-22 mm) exhibit superior plugging performance compared to smaller variants, with effective plugging primarily occurring at intermediate perforation clusters. The study identifies three characteristic migration patterns and establishes critical relationships between knot size, perforation geometry, and plugging stability. These findings provide fundamental insights into the downhole plugging mechanisms of knot-shaped diverters while offering practical guidelines for optimizing diverter selection and operational parameters in vertical well applications. The experimental approach bridges the gap between laboratory simulations and field conditions, advancing the development of more reliable temporary plugging strategies for improved well stimulation outcomes.