Mechanism and Optimization of Rotary Abrasive Waterjet for Well Tubing Cutting: Experimental and SPH-FEM Study

Rotary abrasive waterjet (AWJ) cutting is an effective technique for industrial tube cutting and is widely used for oil＆gas well tubing. This study presents a self-designed experimental apparatus for investigating the cutting performance of rotary AWJ. Based on the SPH-FEM coupling theory, a numerical model for rotary AWJ cutting of tubing was developed to investigate the cutting mechanism and optimize process parameters. Experimental results show that low peripheral speed leads to inefficient utilization of jet energy, whereas excessively high peripheral speed degrades cutting performance; the optimal range is 5.65-7.54 mm/s. Pump pressure below the cutting threshold or high pressure both decrease cutting efficiency, with optimal performance at 50 MPa. Both overly fine and overly coarse abrasive mesh sizes degrade cutting performance, with 80-mesh abrasive being optimal. Increasing standoff distance intensifies jet energy attenuation, decreases cutting capacity, and increases kerf taper; 8.5 mm is recommended. Cutting depth increases over cutting time until the jet no longer has enough energy to cut, at which point the depth stops increasing. A theoretical basis for the design and application of rotary AWJ cutting technology in oil＆gas wells is provided in this study.